P0303 after pcv fitting and spark plug replacement

Hi all,

I have an 02 Lincoln LS V6. This past weekend I had to pull the intake manifolds to hunt down leak(s) causing P0171 and P0174 codes that are preventing me from passing emmisions. I's funny, the emmisions are within passing range, but the Check Engine Light came on for the first time DURING the inspection and the guy says I can't pass with the light on. So, I pulled the manifolds and discovered a deteriorated PCV fitting, though not the infamous elbow. It was the reduction fitting on the end of the PCV tube running from the throttle body. Anyway, I figured while I was in there I'd change out the spark plugs. I gapped them all to 0.052-0.055. Got everything all buttoned up, when for a quick drive up the freeway, then back to the garage to let it idle for 10-20 mins. Now the problem:

Everything was good during the inital starting, freeway drive, and back home. Then when I let it idle while reinstalling the wipers and panels, I noticed that it eventually starting hesitating a bit. I got in and now the car feels kinda shaky and the interior lights are dimming a bit in sync with the shaking. So I plugged in the reader, and two pending codes came up...p0171 and p0303.

I'm assuming the p0171 MIGHT be due to my breaking a tab on the left valve cover breather when removing it. I figured that although it didn't go back in as snug as it was, it would be ok since it seemed that the o-ring engaged. Other than that, I didn't see any other leaks during my tear down.

What could I have screwed up to cause the p0303? I should note that gapping the plugs to spec was not in line with the gaps on the plugs I removed. They were all around 0.043-0.046 or so. But, I wasn't having any of the problems I just described. There wasn't any oil on the plug boots when I removed them. However, I spray intake cleaner in all of the chambers after removing the manifolds but before removing the plugs. So, when I pulled the plugs they were wet and looked oily but I couldn't tell if it was oil or dissolved gunk from spraying the cleaner. Also, it ONLY seemed to be wet on the threaded portion, not the electrode or part that interfaces with the boot. Another note, the manifold bolts may not be torqued to the specified 89 in-lbs. My two torque wrenches go from 120-980 in-lbs and 10-100 ft-lbs. So, I tried to do it by feel. (as a lovely aside, the Ford Motor Company Service Information manual that I have has a lovely typo..."Torque to 89 lbs-ft" in the intake installation section!) I read somewhere that spraying the MAF sensor with brake or intake cleaner could help the p0171 and p0174, so I did that while taking things apart...bad move?? Reader still showing data same as before.

Does anything about this jump out at anyone as a cause for the continued p0171 and new p0303? As of now they are just pending codes, but the car is definitely not idle as nicely as it was before I changed the pcv fitting and spark plugs. Could it be that 0.051-0.057 is not the appropriate plug gap? Again, the ones I pulled were about 0.010 less at 0.042-.046 or so.

Sorry for the lenghty post, but more info is better than less, right?

Thanks for helping!

What kind of spark plugs did you install? If you didn't go with an OEM style plug and put in Bosch Platinum +2 or something, that might be the cause of the misfire. Also, where did you get the gap information? I seem to remember 0.046 being more like the spec listed on the emissions label under the hood of my wife's 2002 LS V6.

I would suggest you verify the appropriate plug gap, re-inspect all intake air tubing to make sure everything is properly aligned and snug, then if you need to pull the manifold again to get to the plug, swap the plug and coil with one from Bank 2 which is easier to get to if it turns out to be a bad plug or coil.

-Rod

Thanks Rod!

I installed Autolite AP104's. I believe these are single platinum plugs. Happen to be the same type that were pulled. I didn't even look at the emmissions label under the hood. I got all the info from the FMC Service Info manual...also found that on several sites. But I believe they all pulled the info from the same place. I'll take a look under the hood and see if we have a discrepancy. I do see the the V8 calls for 0.039-0.043. The following was taken directly from the Service manual:

V6:

General Specifications Item Specification Firing order 1-4-2-5-3-6 Spark plug type AGSF-32FS Spark plug gap 1.30-1.45 mm (0.051-0.057 inch) Silicone Brake Caliper Grease and Dielectric Compound
D7AZ-19A331-A ESE-M1C171-A

V8:

General Specifications Item Specification Firing order 1-5-4-2-6-3-7-8 Spark plug type AGSP-32F Spark plug gap 0.99-1.09 mm (0.039-0.043 inch) Silicone Brake Caliper Grease and Dielectric Compound
D7AZ-19A331-A ESE-M1C171-A

And just for kicks:

89 lb-ft!
file:///C:/TSO/tsocache/BEX_1528/S2X~us~en~file=A0004729.gif~gen~ref.gif

Do you think not having the bolts torqued almost exactly to 89 in-lbs would cause an issue? I'm having the greatest time trying to find a torque wrench starting at less than 120 in-lbs! Think I'm headed to Sears next. Third time I've need one and had to guess. Other two times were on my motorcyle, though.

Thanks again.

A little more...

So, I decided to drive the car into work to see how it behaved and a few more things happened. Hopefully these new symptoms can pin-point the problem.

1: Engine light is now blinking
2: A/C stopped working half way to work (coincided with light beginning to blink).

3: Live stats read "Fuel SYS 1&2 OL, FAULT". Also read, "FUEL SYS 1&2 Eng CoOL Fault" or something similar to that.

4. ATS light is on. This may be unrelated. I recently installed HID headlights and the ATS light has been acting strange since.

Do you have the ability to pull the current codes to see what the code is that is causing the flashing CEL? Flashing CEL will usually also mean the car will go in to limp home mode.

-Rod

Answer to Rod's previous question:

The codes were the same...P0303 and P0171 when the CEL ctarted flashing.

Ok, I tore it apart again last night hoping to find a missed connection or something. I pulled the plugs again and found the rubber insert from the spark plug wrench still attached to the #3 plug! I was REALLY happy that I found that...hoping it would remedy the P0303 (not to mention it was driving me nuts not knowing where that thing went!). So, I cleaned the plug, put a little sealant around the left breather in case the broken tab was causing an issue, and put everything back together. Went for a drive, and same prob! At least it worked great for 20 mins when I first replaced the PCV fitting and plugs. This time, it was apparent as soon as I put it in reverse!

Thinking I should have swapped the coil from 3 to another to see if it helps...that's what's I did this morning. (just so I'm not screwing up, 3 is the one nearest the firewall on the passenger side, right?) Well, no luck on that either...problem still here!

So, I went and bought 2 new plugs to see if the one from the misfiring cylinder was defective...no luck. So far, I've checked all of the driver side bank coils for functionality and all are good...even the one that I swapped from #3. I took them out, started the car and all had a strong spark. How can I check the bank on the other side since I have to pull the manifold back off to get to them? I'm also considering going back to the .046 gap that was present on the plugs I replaced even though the spec and emmissions label says .051-.057.

I keep thinking about having sprayed the MAF sensor with brake cleaner. I mentioned in my inital post that I read somewhere that doing so would help with the lean codes...but could this be the cause of my problems?

The car ran great before, with the exception of the new lean code, so I'm thinking it's gotta be the MAF sensor or the new plug gap. But then again, I'm still seeing roughly the same values for airflow being reported by the scantool. I'm just about to turn into one of those "frustrated enough to take it to the shop" people! urgh

To my surprise, I checked the emissions label on my wife's car and it too states 0.051-0.057 for the gap as well.

You're correct on the cylinder numbering.

Are you sure when you reinstalled the intake manifold and MAF sensor that you got everything connected properly and securely? Is the MAF connection good? If you were careful with the brake cleaner, it should not have damaged your MAF. Your misfire could also be due to the fuel injector on cylinder #3. Did the spark plug from that cylinder look different from the other 5?

-Rod

Yes, the #3 plug did look different...but not on the old ones as there was no misfire then. I think when the CEL started flashing, it shut down that cylinder because it doesn't look like that one was firing. I'm going to loosely connect the two coolant hoses to the throttle body and try to see if all of the left bank of coils are firing. Hopefully I didn't damage the harness.

I'm pretty sure I made all the connections: 2 harness connectors and 2 vacuum (one of which is a double connection) connections in the back, and 2 coolant hoses, 1 vacuum, and two harness connectors in front and on throttle body, and air temp and MAF connectors on intake housing. Oh, and the PCV hose.

As for the MAF and brake cleaner...it could have been air and intake cleaner that I sprayed, I'm just not sure anymore! Which ever one I used, I just spray enough to clear the small amount of dirt that was on it.

Ok, on to the test.

OK, they all are getting spark. Is it normal for it to spark from two places? I took one of the old plugs, put the coil on it, then place it near the exhaust manifold. It looked as if it was sparking from the tip and from the nut portion of the plug. I also switched the boots from the right to the left. The ones on the driver's side fit better, so I put them on the pain in the @ss side. I haven't tried it yet because I'm waiting on the sealant that I put around the breather to cure a little more to avoid problems with the fumes.

If what you're saying about the spark is that you got spark from the tip of the plug to the electrode (where you would expect it to spark) and from the spark plug body to the exhaust manifold, that is probably normal for the test you are performing. The circuit needs to be completed, normally the circuit would be completed through the thread portion of the plug to the head and it wouldn't need to spark because there would be a good connection there. In your scenario, it sounds like you were just holding the plug and coil assembly NEAR the manifold, no direct current path.

-Rod

Well, still no luck. I didn't replace the EGR valve gasket, so maybe there is a leak. I will try that next. If that STILL doesn't work, I'm going to go back to the .046 gap that was on the old plugs. After that, I have no idea what to do.

No go on the EGR gasket. Well, going back in to re-gap the plugs.

Whatever the problem is seems to be isolated to #3. The plug has no evidence of firing despite two days of driving. I just rechecked for spark to be sure I wasn't crazy last night and sure enough, there is spark. I hate to go back to out of spec gaps, but I guess it's worth a shot at this point. If cylinder #3 isn't burning the fuel/air AT ALL, I doubt adjusting the gap will do much to help. Any ideas?

Does the plug appear wet with fuel, or why do you say it has no evidence of firing? If the injector is working but the spark is not, then there likely will be some evidence of fuel there. Of course by the time the upper intake manifold is pulled to access the plug it may have evaporated off.

It might be beneficial to monitor the air-fuel ratio on that bank in a datastream mode of a scan tool to see if the ratio goes rich or lean corresponding to the misfires. I suppose you could have a issue with the Camshaft Position Sensor (CPS) or the Crankshaft Position Sensor (CKP) depending on if you have no spark on that one cylinder or no injector pulse. You mentioned in post #6 above that you've swapped coils and replaced the spark plugs, so you're kind of down to fuel injector, coil wiring, the sensors that trigger each, or compression at this point.

-Rod

Yes, the plug did apear wet. It was slick, shiny, and smooth (coated) as opposed to the dry, brownish, ashy look you'd expect. The other five plugs appear normal.

I don't think my scan tool has the functionality to monitor fuel/air ratio for each cylinder. What might that reading look like? I did, in fact, swap the coil and plug and tested several times that there was spark. I guess I'll go find the CPS and CKP. Is there an easy way to test these? It seems odd that either would conveniently go bad just now. I better go back and look at the injector wiring . It's possible that I pulled one of the connectors a little bit when I changed the pcv fitting. I still haven't gone back to the .046 gap as I just can't see that being the problem.

Man, you're a genius! When I took the upper manifold off this time, I looked in all of the intake chambers. #3 looked just about the same as just after I sprayed cleaner in it...still dry! Turns out the connector to that injector was not secure. When I changed the PCV fitting, I pushed on all of the connectors in the area to be sure they were fully engaged. I heard a "click" on that one and assumed that meant it locked due to it being partially out. WRONG! That click must've been the locking tab breaking since it is now just jiggling around on the connector. So, the connector is pretty much just sliding around. That would explain why everything was great when I first finished the job and went for the initial test drive. The connector worked itself loose while I was installing the wipers and covers and letting the car idle. So, I used a good ole tie-strap and tied the connector to the fuel rail to keep it from backing out. Everything is running great now. Hopefully that stinkin P0171 doesn't come back. That is the only code that came while driving yesterday, even though the car was running crappy.

I'm sure you hear this all the time...but you are a life saver! Thank you!

Mostly good so far. About once every minute or two there slight stutter/misfire while idle. There is also a little hesitation during initial accerleration.

While viewing the live feed on the scan tool, I'm seeing an intermittent, "OL, driCL, using HO2S" in place of "CL, using HO2S." Does this mean anything to you?

I'm guessing OL in this context is "open loop" & CL is "closed loop." I'm not sure what driCL would be, unless that is how your scan tool displays that a drive cycle has not been completed since the codes were last cleared. If that's the case, maybe your small hesitation will go away as the PCM relearns your driving habits.

-Rod

Well, fully seating that connector fixed P0303 and at first there was just an intermittent "stutter" as described a couple of posts back. A day or two later, back to the misfiring and rough idling. Now I'm getting P0306 and the CEL starts flashing after driving a short distance. I've driven over 200 miles since my last post hoping that things would get better, but no luck. I tried swapping coils 4 and 6, but still getting misfire on 6. Guess I have more exploring to do this weekend.

At least your code is on the easy-to-access bank now, that should make things a little better. Good luck with the troubleshooting, and please continue to let us know what you find.

-Rod

I thought I had it all figured out. I pulled the #6 plug and saw it was covered in fuel. So I put another plug on the coil and tested for spark...all good. Put the old plug back in and fired it up...idling rough. So I took the old plug back out to see the spark on it and it was less intense than the other plug I tested. Put the another plug in and it ran great. Drove it for about 20 miles and the stinkin problem came back! P0306 and flashing CEL. When the CEL flashes the scanner indicates "OL, fault" on Fuel Sys 1 & 2. Also, the A/C stops working off and on when the CEL is flashing. I've already swapped the coil with one from another cylinder and the problem stays on #6. I noticed the rubber boot on the coil didn't seat on the coil as securely as the others. Could this be a problem even though the spring is still making contact?

It's really baffling that it has run great for 20-30 mins several times after putting everything back together. I'm almost ready to give up. Monday is the last day I can take it back and get the free 2nd emissions test. I'd sy I'm not going to make it given that it takes about 2 days for the IM system to come back online.

Any ideas? Thanks again for all your help

It really seems like you have a loose connection that takes vibration to start making intermittent connection. It seems like if it were a solder joint or cracked spark plug the could would run fine when cooled down again.

The OL fault is intriguing for the fuel trims, I'm not sure what to suggest might cause that. Can you monitor the fuel trim numbers periodically up to the point of reading OL, or are you just getting the freeze frame data? Are they topping out negative or positive? Maybe the scanner will only accept numbers up to +/-32 before reading OL or something like that.

-Rod

It does seem to behave like a loose connection. I guess I'll pull the intakes again and check the injector connections. I doubt this is the problem given the plug was wet when I pulled it. Perhaps the coil wires are faulty before the connector. Maybe the plug is firing intermittently. Does the computer "shut the cylinder down" if detects something potentially harmful, other than overheating? Say, if the fuel/air ratio is wrong, or the timing is off? It does seem like it runs a little better when the car is cool.

As for the "OL, fault" reading. It wasn't showing it on the fuel trim readings...those all showed numbers, though I don't recall the values. The "OL, fault" was showing where it normally reads, "CL, USING HO2S," or something to that effect. Again, I think it only reads this when the CEL is flashing.

I've spent hours scouring the net trying to find ANYTHING. Could the plugs I put in be causing this big mess? If you recall, I replaced the plug with exact same brand/model (Autolite AP104). The only difference is, I gapped the new plugs to spec. The plugs I took out were gapped closer to the V8 spec. I've been reading that we should only install motorcraft plugs. Of course most times this is coming from a dealer tech. In your experience, is there any truth to this? After all this time and effort, I'd hate to take it to the repair shop only to have it be something as simple as wrong brand plugs, or bad gap.

By the way, I can't believe I haven't tried to gap them back to what they were, 0.045 or so. As an engineer, it REALLY bugs me have something out of spec, especially on mass produced items. My industry typically deals in one-off items, so the specs are usually floating from one thing to the next. But on an automobile, you'd think the same spec would apply from one identical vehicle to the next. Then again, variations in the manufacturing process could give rise to the need for different values in a particular vehicle. ARGHHH...just try re-gapping, already! Sorry, having a melt-down over here! :)

I don't think single platinum Autolite plugs would be the problem. I had NGK Iridiums in my LS V8 and didn't have any problems from them. My wife's LS V6 still has the original plugs in it so I don't know if hers would have a problem with Autolites, but I doubt it.

She's trading her LS in next week for a new MKZ so after next week I'll no longer have my reference vehicle.

-Rod

I know you can do it, the LS & JAG have the same DNA, and health issues.

http://www.jaguarforums.com/forum/showthread.php?t=27038

Thanks for the link! I was actually looking for an S-Type forum to troll around in since these cars are essentially the same.

Ok, I replaced 4 out of six COP boots. Only two of them had the more robust "star" cross-section design. The other four were the plain ole cylindrical type. Also, a couple of them would not even hold the plug in place once inserted. The spring would just push it out. I didn't think anything of it since the whole thing is bolted down when installed. After reading about micro-cracks and possible moisture infiltration, I thought changing out the other four would be a good idea and may even be the source of my problem. Well, I'm happy to report that she is running well after the replacements. I only took it for a 30 mile test drive. About 20 Hwy and 10 city. During that time I also stopped several times and let the car idle for about 15mins each. So far so good. I was almost all set to order a set of COPs. I almost hit "Buy It Now" last night while on Ebay. Then I thought, "let me try to boots first before buying these."

I'll post an update tomorrow or Tuesday. Hopefully I'll be reporting, "ALL IS WELL!"

Again, thank you for all the help!

Went all day with no problems. AND passed my emissions re-test. Sweet! I'll give one more update at the end of the week.

Well, hopefully this marks then end of this thread! 175 miles and still good!