1991 Cutless supreme 3.1 stalling

[mandude]

I have had this car for about a year now.
it has 216,000 miles on it.
ever since i have gotten it, it has run rough at idle.
When i am sitting at the stop light and the car is in drive
it stalls out if i dont keep my foot on the gas,
I think this happens more when its warm outside.


Any suggestions?

[91 bird]

the stalling sound like it could be the IAC valve (idle air control). it may be cruded up or if it is the original, it could be shot.

[toddman67]

Try cleaning the throttle body. I took mine off, remove the sensors cleaned all the passages, bore, plate etc. Check IAC valve and seat. if it's gummed up, best to replace. Tooth brush with fuel injector cleaner works best and blow out w/air when through.
Also check for vacuum leaks. Due to the age, It would be a good idea to replace them all!

[jwokmuba2]

my wifes 93 cutlass had the exact same problem, only thing that was different was that the car never warmed up to 100 , so we had a friend look at it who happens to be a gm tech and he replaced the thermostat of all things, now the car runs good with 225,000 miles on it

[mandude]

I would just rather sell the thing. or trade it for somthing else.

Its white with grey trim.
it has Pontiac grand am rims on it.
with new tires.

the body is is good shape little rust.
the muffler is shot.

the interior is grey. kinda beat up.
no rips or tares. just burn holes.

keep in mind im a 19 year old.

[awe341max]

I have a 92 with the same engine and just under 200k miles with the exact same issue.

I have checked and replaced the following with no change in symptoms.

IAC (cleaned entire intake as well)
EGR
plugs/wires
PCV
thermostat
fuel pressure regulator
injectors
fuel filter
fuel pump gives good pressure
O2 sensor
checked coil packs
checked for vacuum leaks
replaced ECM

With all this done you would think the car would run like a champ again but it still runs exactly as the OP describes. I am at a complete loss on this one. Anyone have further ideas?

BTW, hot or cold outside doesn't seem to make a difference for mine, however it can sometimes be very hard to start if it has been raining. Though that is a new symptom in the past few weeks and might be unrelated. The hesitation at idle and the stalling has been happening for almost 2 years now. The car does run great on the highway though.

I think that the oddest thing though is that it gives a MAF code if you let it sit and idle for a while. But this engine does not have a mass airflow sensor.

[jwokmuba2]

hey, max

i sold the car to my dad and he changed alot of what you have changed, then i talked to one of my friends dads who is a GM tech and said there is probly carbon build up in the car somewhere, get on the highway and floor it a couple times, up to about 100 mph, so my dad did this and what do you know, the car made a load sputtering noise and choked out then TOOK OFF, i guess it blew the carbon out the exhaust, car has been running great ever since, i guess you can try this mabey it will work for you to, good luck,

[Ginsengbull]

PCV tubing from the rear valve cover gets cracked, and sucks a lot of air, diminishing vacuum.

Another problem is the EGR valve gets hung up with soot. Can be tough getting the right replacement. I clean them out with gun-cleaning brushes, then lube them with powdered graphite.

[maxwedge]

Good info but this is a 3.5 year old dead thread, check the dates before posting, thanks.

[jinxyzboi]

Max. a lot of oother folks read these problems other than the original person that posted. Whats the critical time if it helps someone ya know