bucking and jerking is back

[SRamsey625]

help me out guys. I had a bucking and jerking in my 99 for a while. It seems to be worse the colder it gets. As the van warms up, the problem goes away. I've had the fuel pump, fuel pressure regulator checked out. Both were good. replaced fuel filter and seafoamed it. Seemed to help it run better but it still bucks when cold. I have no idea what to check next. I've had this problem for about a year. Looks like my last choice is to take to my mechanic and spend gobbs of money just to diagnos the silly thing.

[rivguy]

the 3.8 windstars have problems with upper intake gaskets and mounting bolts that cause cold start missfires - as the engine warms and the intake expands the problem goes away

[SRamsey625]

Originally Posted by rivguy

the 3.8 windstars have problems with upper intake gaskets and mounting bolts that cause cold start missfires - as the engine warms and the intake expands the problem goes away

Thanks Rivguy. What is the remedy? replace gaskets and/or bolts? I replaced the isolator bolts about 4 months ago but didn't help. Should I go ahead and replace the gaskets as well?

[KPVSR]

the bucking and surging could be from the IAC. Just under $100.00 for a new at the dealer. I just got one and it is designed slightly different from the original.
A quick way to check to see if your seals are the problem, press down on the intake with some force. If you can get the engine to idle well when doing this your problem is probably from the seals.
Ken

[rivguy]

the gaskets are a very known problem - you should replace the gaskets and bolts as a set - if you have new bolts then just the gaskets - the rubber in the gaskets gets hard and stopps sealing - also when replaced you will noitce a different color due to the new rubber being used to prevent this problem from happening again

[harper992]

also check your plug wires, mine has came off the plug a bit and caused the same problem! good luck
Harper

[pb1998]

Hi! I just had my van in the shop for what sounds like the same thing. When I got in to start it in the morning, when engine was cold, it started to buck but when it warmed up it was fine. Well i took it to my mechanic and he did diagnostics to find that the cam sensor was broke. If it is only the sensor which thank goodness it just was, it is only $20. But, he of course had to charge me $180 for labor!! So, try that and I hope this helps!!

[SRamsey625]

That's good to know. The CPS was one of the things I was going to check next. I did replace both upper and lower o-rings today. I noticed that bolt number 10 would not tighten as the insert was just spinning in it's hole on the lower plenum. I replaced with a nut and bolt (slight pain in the neck) and managed to get it tightened down to the 89 in lbs. I won't know until in the morning if that fixed it or not. If not, I will definately check the CPS. Thanks.

[SRamsey625]

Well, shortly after this post, the van finally threw up a CEL. Had it read at Autozone. 340 Cam Position Sensor broken circuit. Pulled off the connector and it practically fell in half in my hand. $10.12 (got good connection) PROBLEM RESOLVED!

[Stan the Man]

I think I may have the same problem. My CEL came on a couple weeks ago, but no noticeable drop in performance at first. Since a few days ago, it will stall at the beginning of acceleration and during idle.

About a week before the CEL came on, I heard, and continue to hear, a screeching sound, which I thought (think) is coming from the water pump bearing.

My wife got tired of wondering & took it in to get the codes read. The mechanic, who is about as trustworthy as a mechanic can be, said about 8 different codes came up. He said it's usually a CAM sensor. I could've killed my wife for not getting the actual code numbers.

Any way, my question is: 1) assuming it's a bad CAM sensor, could that cause a screeching sound; and 2) how much of a pain is it to change it myself? The mechanic told her it's about $35 for the part, and $25 to put it on.

I know it's Christmas, but any help would be greatly appreciated.

[wiswind]

I replaced the Camshaft Position Sensor on mine.
Very easy.
There are 2 screws on the top of the sensor and the electrical connection. Do not mess with ANY other screws or bolts as you do not want to change the position.
The Camshaft position sensor is all that is left of the old distributer that cars used to have.
It is on the passenger side of the engine, on the top...but down under the upper intake manifold....more like between the upper intake manifold and the drive belt (alternator, water pump, power steering).

[SRamsey625]

They are not that hard to change but I would have to actually loosen my p/s pump so that it would clear it. First, get a long screwdriver or socket extension and put it against the base of the cam pos sensor assembly and the other end to your ear. (extension works best) If that is causing the screech, you'll know without a doubt. Be sure to mark clearly where the cps is positioned before loosening the hold down bolt. When you take the cps (the plastic part) off of the assembly, take careful note of the position of the rotor and put the rotor of your new cps assembly the same way before removing the old one. This is the process I was using when I realized that it was getting late and I had to go to work in the morning. So to get me by until I could have more time with it, I just lifted the old one as high as I could before hitting the p/s pump and gave it a good shot of WD-40. That was back in september. It hasn't screeched or bucked since. Took new part back and got my money back. Cheap fix. How temporary remains to be seen. Just to clarify. If you hear it screeching, and the cps is the culprit, you will be dealing with the whole assembly not just the top. Sometimes, when the plastic sensor breaks, a small piece can get into the assembly causing the screech. Just changing the plastic sensor will not solve your problem. Changing the whole assembly is a quite a bit more labor intensive as you will have to loosen the p/s pump, remove the lines and the w/p inlet. Trust me. try the WD-40 trick first.

[Stan the Man]

I replaced the cam position sensor cover, and it looks like it needed to be replaced. My new one has a flat piece that looks like it rests on the contact inside the CPS. On my old one, nothing at all was there. So it was definitely a good thing to replace it.

My van no longer acts like it's going to stall out now during idle. Just need to take it out for a test drive now. When I re-connected the battery cable, the CEL was off. I let it run for about 10 minutes. When I cranked it up a few minutes ago, the CEL was back on!

The screech is still there, too, and I think I know what it may be. As I was checking out the belt as it was running, I saw that my A/C pulley wasn't turning. I turned the A/C on full blast, & it still didn't turn.

My question:
1) does the A/C pulley only turn when the A/C is on? If it's supposed to turn, maybe it's putting too much strain on the belt, maybe damaging a bearing somewhere else? Is it safe to drive like that if the A/C pulley is supposed to turn?

2) Will I need to drive the van for a while for the CEL to go off if it was the cam sensor causing it to come on?

I was really hoping the cam sensor cover would solve the problems. I should have known it wouldn't be that simple.

As always, any advice is greatly appreciated.

[SRamsey625]

If I were to take a guess, I would say that your A/C compressor has gone amuck. Does the air get cold? The compressor has a clutch on the pulley that engages and disengages allowing the pulley to turn at all times while the compressor turns as needed. (Your A/C compressor also engages in the winter when you have your defroster on to reduce moisture in the air therefore defrosting more effectively) If that clutch goes out, it will sieze and the belt will just slip over the pulley (screech). If you've never done an A/C before, you should let your mechanic tackle that one. You would also probably smell a burning rubber smell. I wouldn't drive any great distance. Once the belt goes, you lose everything, most importantly, water pump. Then engine is soon to follow. If your cam pos sensor assembly was screeching, it would be sporatic and only when cold. If it is a constant screech, have that A/C checked out...Hope it helps

[Stan the Man]

So if I'm understanding correctly, the A/C pulley should always be turning, right? If it is, then that's my problem, all right. I'll be taking that in right away. In the meantime, would keeping the defroster turned off make a difference? Is there anything I can do to minimize potential damage?

Regarding my other question, will the CEL reset or go out once I've driven it for a while?