New coil; still missing/bucking; '99 3.8L

[Windywoes]

I installed the new coil purchased through Amazon. Fit well. No issues there. Unfortunately Windy is still bucking/missing when slowly accelerating from low speed and low RPM while in 3rd or 4th gear.

To date I have installed new wires (plugs have about 25,000 on them), new DPFE, new coil, 2 cans of Berryman's in the past 12 months, checked EGR function, cleaned EGR ports, and I have checked for vacuum leaks as best I can. Windy has 138,000 miles on her.

Unless someone chimes in my next plan of attack is:
- re-check the function of the DPFE
- new Autolite 105 style plugs that are supposed to be a bit longer than the 700 series I now have installed
- remove injectors for inspection or cleaning
- check fuel pressure
- install new fuel filter (current one has 15,000 on it)

Thanks to anyone who offered help previously.

[catvents]

Originally Posted by Windywoes

I installed the new coil purchased through Amazon. Fit well. No issues there. Unfortunately Windy is still bucking/missing when slowly accelerating from low speed and low RPM while in 3rd or 4th gear.

To date I have installed new wires (plugs have about 25,000 on them), new DPFE, new coil, 2 cans of Berryman's in the past 12 months, checked EGR function, cleaned EGR ports, and I have checked for vacuum leaks as best I can. Windy has 138,000 miles on her.

Unless someone chimes in my next plan of attack is:
- re-check the function of the DPFE
- new Autolite 105 style plugs that are supposed to be a bit longer than the 700 series I now have installed
- remove injectors for inspection or cleaning
- check fuel pressure
- install new fuel filter (current one has 15,000 on it)

Thanks to anyone who offered help previously.

Just before to make another attempt, maybe you could just check the spark plugs ( at least the 3 one at the front) and see if there are clean; my winnie has a lot of milage, and from time to time I have to clean 1 spark plug ( fortunatly at the front of the engine), because the valve seals leave a little bit of oil coming inside of the combustion chamber, and cause a light misfire of the spark plug.

[CnlK]

My winnie exhibited similar problems, it would occassionally buck at hwy speeds and die at idle. In my case it ended up being the mass air flow sensor. No codes were ever set. When the problem became quite frequent I tried cleaning the MAF, that helped some so I bought a used one for $60 from a boneyard and havent had a problem since. Again the bucking was intermittent, not a continual problem. Another area to consider is the camshaft synchronizer, is there a whine coming from the synchro, if so pull sensor off and see if there is any damage evident, if so the bearings in the synchro are bad. Others have had problems with the fuel pump relay. In the 2000 the horn & fuel pump relay are the same, try swaping relays. Just a few thoughts for areas you haven't considered yet.

[Windywoes]

OK. Thanks to you both. Cleaning the plugs and the MAF are not difficult or expensive so it is worth a try. I did look at just one of the front plugs and it looked fine, but I will check all three again.

[Windywoes]

The front 3 plugs are in excellent condition (APP 765's). I cleaned the MAF with CRC MAF cleaner. Still bucking. Onto the the other items on the list. I will be back.

[12Ounce]

Originally Posted by Windywoes

.....- new Autolite 105 style plugs that are supposed to be a bit longer than the 700 series I now have installed
......

Does this mean the top of the plug is longer? OK. Or this mean the threaded portion is longer? Not good! I would not want any greater protrusion toward the piston crown.

I'm assuming you have no CEL's? Have you tried disconnecting/plugging the control hose on the EGR valve? Drive until you get a CEL and have the codes read. Look for any codes that don't have to do with the EGR.

[danielsatur]

Did you reset the codes, after your Fix?
Anytime you throw a DTC, Fix, and reset code, otherwise you must go through a drive cycle.

Example:

See http://www.automotiveforums.com/vbul...d.php?t=970921

No AutoScanner -
1) disconnect your battery
2) Touch the pos side cable to gnd.
3) Connect your battery back up.
This will reset all your Computers + control modules to a know state, so you can fix this van.

[serge_saati]

What is the heat range, plug gap, thread diameter, thread lenght, and all specs of your plugs? They should meet the OEM specs of your Windstar to work great at all RPM range.
The gap should be 0.054" and the Heat range should be 5 (hottest). Not all brands use same heat range scale.

The more is hot, the more the internal thread is long (not visible).

I already had a Windstar 99 3.8L with NGK TR55GP plugs, and they work perfectly.
Your plug should look like this:
http://www.ngksparkplugs.com/part_fi...tnumber=TR55GP

I'm sure you DON'T need a new fuel filter.

I don't recommand you to disconnect the battery to reset PCM, it'll be worse the 5 first minutes, then will remain to the same problem.

If you're sure that plugs are good, check the IMRC. Cleaner may not be enough.
At which RPM do you feel the difference?

Have you replaced alternator recently? A bad alternator can damage the PCM partially and result in engine roughness.

[Windywoes]

Wow, that's a lot to reply to.

No codes have ever been set with this problem. I may pull the vac hose to the EGR to see what comes up in the codes.

Both the APP 105 and 765 plugs are listed for the '99 3.8L Windstar. The 105's appear to have a longer threaded section than the 765's now in the engine. One fellow who had this problem told me he got rid of it by switching to the 105's. Some say it is good and some say it is bad. These plugs (the 765's) worked perfectly for almost 25,000 miles, it is only the past 5,000 miles or so that I have had this problem.

Alternator was new last year.

I have a code scanner so I never clear CEL's by disconnecting the battery.

Problem happens in 3rd or 4th gear, low RPM's, usually while trying to climb a hill or slight grade under low acceleration. If you tip into it the miss never happens. It has been getting steadily worse in the past month and seems to be more prominent on damp days.

To repeat what I have done so far:
-new coil
-new wires
-new DPFE,
-cleaned MAF
-checked plugs
-checked DPFE function
-looked for obvious vacuum leaks
-IMRC links are connected and both IMRC's seem to be functioning as best I can see

Thanks, All

[serge_saati]

You've done a lot of things! It should be frustrating when nothing work.
Test your fuel pressure. It could be the fuel pressure regulator.
At idle, pressure should be between 28-45 psi (36 average)
when pushing on gas, it should be between 45-65 psi.
check also the air filter
if it's not working, next step is try to change the PCM.

[Windywoes]

I don't have a pressure tester.

I just did a test by plugging EGR port and the vacuum line to the port and drove it for about 15 minutes. I noticed no difference in how it ran. It still misses/bucks going up hills. I did not get a CEL either.

[serge_saati]

You said that you checked obvious vacuum leak. You mean vacuum hoses? Cause it can coming from the inside of intake manifold too. Use a vacuum gauge tester.

I remember someone get exactly the same problem as you describe with a 2000 Windstar. It was the PCM in his case. Because these kind of symptoms are frequents, I can't guarantee that it's the PCM.

BTW, try to avoid up hills at most, they are very bad for the auto transaxle.
And always climb it w/o the overdrive.

[danielsatur]

Is this a WOT with random Misfires ?

See http://www.automotiveforums.com/vbul...d.php?t=882939

Suspect a dirty throttle body or bad MAF sensor, because of PCV and EGR Emissions.

Yon need alot of Air for 200HP, not bad emission gunk.

[serge_saati]

Originally Posted by danielsatur

Is this a WOT with random Misfires ?.

Originally Posted by Windywoes

Unfortunately Windy is still bucking/missing when slowly accelerating from low speed and low RPM while in 3rd or 4th gear.

not misfire, just bucking

[12Ounce]

Originally Posted by Windywoes

.....I just did a test by plugging EGR port and the vacuum line to the port and drove it for about 15 minutes. I noticed no difference in how it ran. It still misses/bucks going up hills. I did not get a CEL either....

The EGR will only be activated during periods of high rpm and loads ... so it may take quite a few highway miles to trigger the CEL.