Hello all,
Would you please let me know what could it be?
Symptoms: Engine hesitates and RPM flow badly as on idle so while on drive when engine is rather cold :( . When temp is ~90 DEG C, the behaviour becomes better but not as good as it should be . CE light doesn't work at all so codes can't be obtained.

Action items that I should perform:

1. Spark plugs and wires check/replace
2. EGR check
3. ???

Any suggestions or your own experience would be highly appreciated.

Many thanks in advance,

I'm going to visit service shop this weekend but just try to figure out if I could do any basics by myself.

Please keep me updated I am experiencing pretty much the same problem right now.

Thanks

my 88 LeSabre had the exact same problem. I replaced the timing chain and the problem went away for the most part..

i think u should check your air filter first off. the only reason that it runs better when its cold, is because the engine increases the fuel demand, and not the air.we had symptoms similiar to those on my '84 tempo. we replaced the air filter, and we had a semi-decent running car.lol

Air filter has been changed 1000 miles ago. Had already checked it. Looks like new. Will dig deeper to figure out the cause.

I would replace the check engine bulb, and then retrieve the codes. You'll have to take the instrument panel apart, but it sure would help you retrieve codes....

I just went through the hestiation blues on my 91. Did the spark plug thing, checked to see if my wires were leaking. After plug change, still no good. Wires were not leaking. Turned out to be my power pack. Once that was changed, engine ran great.

When I would watch the rpm gage, they would jump. Not sever jump but more like a bounce. Cost $112.labor included.

Cobra

An erratic idle in a car that drives OK otherwise is 90% a gummed up Idle Air Control (IAC) in my experience . This is what controlls your idle and if it does not react quickly the ECM will increase the command until when the IAC finally does move it goes too far so you have an idle that is constantly too much or too little. Works better when hot just means the gum is thinning. Have also seen it cause the engine to die coming up to a stop. Will not set a code if just gummed up.

On a "C" engine the IAC is under the throttle assembly and is held on with two little philips screws (put something under for them to fall on when you drop one (I always do) so it does not go under the intake manifold (won't hurt aything but is an oddball size so do not lose).

Remove and spray with carb or tuner cleaner until clean and spray/wipe out the recess in the manifold it fits into. Do not try to push or pull the pintle in or out as it is a worm gear inside and they do not like it, just spray/wipe until clean.

Have to drive over 38 mph for the ECM to reset it.