Thread: Engine takes too long to idle

Hi!
I have a gp 1995 3.1L
when the engine is cold, it takes a while until the engine idles.
at start he is at about 1500 rpm for a few minutes, then at around working temp. the rpm is around 900.
what is the cause for that? is there anything to do to shorten the time to reach 900 rpm?

(pcm replaced, throttle body cleaned, i guess theres no vacuum leak).

thank's!

Sounds normal actually. The pcm commands a higher idle speed during startup. Especially when it's cold it's going to command a high idle to try to reach operating temps sooner.


And the 900 at idle seems to be about right for an automatic.

The problem is that the ambient temp is not so cold...
and a couple of months ago it worked perfect. a few seconds at 1500 rpm and then dropped to 900. now it's a matter of minutes.
the main problem with this rpm is that the tranny knocks when shifting into gear.
could it be the temp. unit that goes to the computer?
IAC?
any solution?

I see. Well how is you're temp gauge on the dash working? They should be the same sensor.

It could be a dirty IAC, Try taking it off and cleaning it with some carb cleaner or something like that.

the dash gauge is o.k.
the entire throttle body has been thoroughly cleaned about a month ago.
i have heard there is some kind of step motor around there. could it be it?

thanks!

Right the Iac is measured by steps. I think usually when they go bad they do just the opposite. But it may be worth taking off and cleaning the inside of it. Where the air comes out.


Maybe also spray around the intake with some carb cleaner to check for vac leaks. And all the other usual places. The IAC on the later year cars have an o-ring to seal it. So maybe that would also be worth checking out too.

thanks! I`ll check it out.

Let us know and we'll go from there.

OK guys!
it seems like the problem is now resolved!!!
first- i took the entire throttle body apart. cleaned everything thoroughly.
especially the IAC which was dirty as hell.
second- I've replaced the thermostat, which looks to me like it never been replaced since the car went out from Detroit... (approx. 14 yrs.)
third- I've added the BG ATC (Automatic Transmission Conditioner).
now everything seems working just fine! the idle is reached very quickly, the car has returned some horses to the engine, and the tranny won't knock! the gears are shifted very softly.
bottom line- I'm H A P P Y ! ! !
Thanks!

woudl this also cause a 94 to bounce its revs at start up and idle there after, but also drive down the road ok? i just got this car, and love it already, but its hard to start, have to gas it to start, and then the revs bouce once it will sustain itself

yea, check it IAC

ok my account, capnfangsgp wont let me in.. so i made this one.. thank you ill clean up the whole intake.

can someone post a pi of where tha iac is on a 94 with the mpfi engine?

alright cleaning the throttle body and the iac fixed the idle being too high, at 1000 rpms is ok for now, and im not sure what but somehow i fixed a vaccum leak i had and also did something to fix that surge b4 i cleaned anything.. but thanks guys for the great help now i have time to make my welcoming post for myself!