Rough Idle--IAC?
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Rough Idle--IAC?
The car has been othewise driving very well, except at idle. When I come to a stop (transmission in drive), the idle is quite bumpy and rough. When this first started several months ago, I squirted some throttle body cleaner in the bores and wiped out any gunk. This helped for a short while but then the rough idle came back. So the next thing I did was pull the IAC. It had a coating of black stuff on the tip of the pintel so I cleaned that and also sprayed throttle body cleaner in the IAC port on the throttle body. I reinstalled the IAC but the idle is still bumpy.
Is there any easy way to tell if the IAC is working correctly or is there another possible culprit.
Thanks.
Is there any easy way to tell if the IAC is working correctly or is there another possible culprit.
Thanks.
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Re: Rough Idle--IAC? (AGENT 86)
Seems like about 700-800 rpm reading off the instrument panel tach. At best, the idle is smooth with intermittent roughness. At worst there are times where it is consistently rough. The condition seems to change based on driving conditions (i.e., when the engine is cold versus after it's been running for a while). In either case, the car seems quick and smooth once coming off idle and driving.
Is there some quick IAC check such as unplugging the electrical connector while the engine is idling and see what happens, or is that a no-no.
Is there some quick IAC check such as unplugging the electrical connector while the engine is idling and see what happens, or is that a no-no.
Burning Brakes
Joined: Dec 2003
Posts: 770
Likes: 0
From: Madison Mississippi
Re: Rough Idle--IAC? (DougSilver)
Doug, I had a problem with my idle air control and it would idle low or high or sometimes normal. It sounds like you could have a vacuum leak somewhere or possibly an ignition miss. It is hard to tell without more info. How many miles since your last set of plug/wires? :confused:
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Re: Rough Idle--IAC? (RUBYREDVETTECARD)
I had the opti replaced and new plugs/wires about 7000 miles ago (October, 2002). Those items were replaced due to the car missing under load at all speeds. The current problem is only at idle but all other speeds and conditions seem fine.
Burning Brakes
Joined: Mar 2003
Posts: 1,174
Likes: 6
From: NW MN
Re: Rough Idle--IAC? (DougSilver)
:lurk:
I have the same problem with my 86 and I've done all the tune-up stuff plus new oxy sensor which did help everything across the board but the idle still a little rough. My next step might be the injectors as my car has 100K on the clock.
I have the same problem with my 86 and I've done all the tune-up stuff plus new oxy sensor which did help everything across the board but the idle still a little rough. My next step might be the injectors as my car has 100K on the clock.
