Idle Problem
Thread Starter
Intermediate
Joined: Sep 2004
Posts: 31
Likes: 0
Idle Problem
I have a '87 vert. The car runs great, but lately it doesn't seem to be able to hold the idle. While driving, it's runs smooth but when I get to a stop sign or traffic light, the rpm's begin to drop and 70% of the time the car will stall out. Any opinions? Thanks for you help.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
with checking for vac. leaks, but I'm a strong proponent for using SeaFoam for carbon removal, and your idle is controlled by the IAC, which we've all found to be a carbon magnet.Now alot of guys are cleaning them...but you can't just buy the IAC gasket...found this out from a forum budy, it only comes with the TBI gasket...so, you might be better off just spending $29. for a new IAC, which comes with the gasket.If you decide you're going to do this, check out this post.
http://forums.corvetteforum.com/show....php?t=1389867
Good luck, BTW, mines an 87 also, friggin plastic vac. lines lol
Instructor
Joined: Apr 2006
Posts: 117
Likes: 1
From: east haven ct.
Idle Problem
Are there any codes, I had the same problem with a 91 great driving but when I stopped the Idle was bad.I had a 32 code so I changed the egr valve much better but still not right.This year had to go in for emissions failed and the outcome was the brake booster it was cracked and also had a bad vacuum.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
with vaccum leaks, IAC, and now the TPS. From all the post on poor idleing C4 vettes on here, I have now made cleaning the TB a maintenance item. Check for vacuum leaks and clean the TB and IAC passages by taking the TB off. First, insert a paperclip in pin A and B of the ALDL. Turn the key on and wait about 1 min. and disconnect the IAC under the TB. This will block the passage for setting minimal idle and TPS. Block the front wheels and set emergency brake and crank up and put in drive. Use a torx bit on drivers side pleneum above the throttle linkage and set RPMs to about 400-500. The TPS will have to be reset also with any change in the butterfly in the TB. You will have to use a Volt meter for this and it should be set at FSM says .5v closed throttle and 5.0v at WOT (the TPS is set with engine off and key on). Also I have seen recently that the EST wire should be disconnected to do this so the ECM can not control timing. This will set a code when disconnected.
When these steps are done cinnect the IAC and crank.
When installing IAC make sure the tip is no further than 1 1/8" from the flange and can be wiggled back.
I'm sure I missed something.
