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Discussion Starter #1 (Edited)
I've got demons and they live in my girlfriends 91 Fleetwood (4.9L, FWD)

Heres' the problem: The car has an irregular idle. It revs normal and will unexpectedly drop idle near the point of stalling, quickly rev to normal and repeat. Again and again and again acting like a fan with a weight on one of its blades.

Only one code continually surfaces on the DIC but it is in regard to the torque converter. The check engine occasionally flickers on but never when it is idling poorly. I think I've checked everthing only other problem I found in my search was a broken vacuume line off the MAF. I disabled the automatic idle control module and set a standard curb idle using the fixed idler screw on the throtle body.

I'm obviously overlooking something but I'm out of ideas. I just don't want this car to die on her in the middle of winter. So any ideas are appreciated.
 

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My case (95 DeVille, 4.9 L).

My problem was missing firing at any conditions. It didn't happen
all the time. Most of the time, the car was running fine...

Fuel filter replaced, fuel pressure OK, ignition OK, ignition module
OK, occationally "No cam reference" error (I forgot what # it was),
but it didn't come on until the problem became quite serious.

It turned out that it was caused by the bad distributor. I am
still not sure if it was a mechanical problem in the distributor
or the pickup coil problem. Because the distributor looked fine
and moved fine. The pickup coil was fine when it was statically
tested. But after replacing the distributor, the problem is gone.
That's all I know for sure.

But your case sounds like a vacuum problem or a bad ground
that giving trouble to the computor...

Does your car act funny while running as well?

Good luck!

Slick Black Cadillac said:
I've got demons and they live in my girlfriends 91 Fleetwood (4.9L, FWD)

Heres' the problem: The car has an irregular idle. It revs normal and will unexpectedly drop idle near the point of stalling, quickly rev to normal and repeat. Again and again and again acting like a fan with a weight on one of its blades.

Only one code continually surfaces on the DIC but it is in regard to the torque converter. The check engine occasionally flickers on but never when it is idling poorly. I think I've checked everthing only other problem I found in my search was a broken vacuume line off the MAF. I disabled the automatic idle control module and set a standard curb idle using the fixed idler screw on the throtle body.

I'm obviously overlooking something but I'm out of ideas. I just don't want this car to die on her in the middle of winter. So any ideas are appreciated.
 

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Discussion Starter #3
Mystery

Hey, thanks for taking time to help my situation 100.
The car runs normal while in motion it problem only really emerges when turning corners (the harder the more predominant the problem), and when idling regardless of how long or what conditions. This ones got me scratching a bald spot.
 

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Re: Mystery

Slick Black Cadillac said:
Hey, thanks for taking time to help my situation 100.
The car runs normal while in motion it problem only really emerges when turning corners (the harder the more predominant the problem), and when idling regardless of how long or what conditions. This ones got me scratching a bald spot.
When turning corners? The first thing came in my mind is
fuel deliverly problem. The fuel pump may not be able to
pump enough fuel when the car is turning because fuel moves
to side... What do you think? I would check the fuel pressure
to see if the pump is healthy.

But I am not sure if these two situations (turning corners and
idling) induce the same problem or not.

I can't help you much, huh? Good luck!
 

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I had the same problem with my 92 Sedan DeVille. My fuel pump ended up being the culprit. Mine got to the point of when i stomped on the gas, my car stuttered.
 

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Discussion Starter #6 (Edited)
What's strange is I paid a mechanic (I know I should have done it myself, but it was cold out) to put a new fuel pump in when the gas tank was replaced (it sprung a leak on one of the welds). If I paid for the pump and the install labor and that sleeze never put a new pump, I'll...Well... I don't know. I don't know what the best way to pinpoint/resolve this problem is.
 

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Are you saying it started after the tank was replaced??

Maybe when the pump was reinstalled in the tank,
the filter attached to the inlet of the pump was not
straight or was kinked, so the pump can't suck the
fuel well. Well, but if it is the case, the problem should
happen any time... Sorry that I can't help you much.
 

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Discussion Starter #8
Hey, any help is good help. I probably would have over looked the fuel pump (being that it was supposed to be replaced and all) alltogeather. I am currently attempting to look into the problem more deeply now. Thanks
 

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I've had that same problem twice now... You'd be going on an offramp and BOOM... nada. Both times it WAS the fuel pump, they're a really bad design (and expensive) on these cars.
D.
 
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