Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: Jamie on May 29, 2007, 08:52:32 PM

Title: High Idle???
Post by: Jamie on May 29, 2007, 08:52:32 PM
I have a 88 turbo coupe 5 speed that keeps on idling high around 1500-2000 rpm... it doesnt seems to go any higher than that, then sometimes it will flip the engine light on and start running rough???? once you bring it off idle it works fine.. my first guess was a vaccum leak but i cant seem to see anything??? i was thinkin maybe an o2 sensor or idle control sensor... what should i check first???:wtf:
Title: High Idle???
Post by: skittle on May 29, 2007, 09:33:01 PM
Same thing happens with mine. All i do is turn it off and re-start it and it idles fine after that.
Title: High Idle???
Post by: Jamie on May 29, 2007, 09:43:23 PM
Mine did that off and on for a while now, and every once in a while i can shut it off and restart it and it idles normal but most of the time it stays high... It doesnt help that it sits all winter and i havent been driving it much in the last couple summers
Title: High Idle???
Post by: grutinator on May 29, 2007, 09:53:50 PM
i'd take off the IAC first and clean that out. it may be carboned up and sticking. also try gently tapping it with a wrench when the cars idling, see if that smooths it out any...if it helps, go ahead and try to clean that out. i'd think if its a vacuum leak big enough to make the car idle too high, you'd hear it. but with a cold engine at idle, u can try to spray some carb cleaner around the intake s and such, if it bogs down, u found a leak. but personaly, i'd clean the IAC first, ive had more problems with poor idle from that then anything else...although mine is the notorious for sticking 5.0 IAC
Title: High Idle???
Post by: Jamie on May 29, 2007, 10:09:43 PM
thanks i will try that tommorow!!!
Title: High Idle???
Post by: CougarSE on May 29, 2007, 11:22:36 PM
Quote from: grutinator;150678
i'd take off the IAC first and clean that out. it may be carboned up and sticking. also try gently tapping it with a wrench when the cars idling, see if that smooths it out any...if it helps, go ahead and try to clean that out. i'd think if its a vacuum leak big enough to make the car idle too high, you'd hear it. but with a cold engine at idle, u can try to spray some carb cleaner around the intake s and such, if it bogs down, u found a leak. but personaly, i'd clean the IAC first, ive had more problems with poor idle from that then anything else...although mine is the notorious for sticking 5.0 IAC

I once pulled codes on a guys car while working at autozone.  He was all scared and I could tell he didn't think I knew what I was talking about.  It was idling high and the MIL was on.  I showed him the part and with one good wack of a crescent wrench it worked idled right back down.
Title: High Idle???
Post by: Inspiribomb on May 30, 2007, 02:09:23 PM
IAC and TPS are both suspects.  Mine used to do the same thing.  I readjusted my TPS and it rarely does it anymore.  You can check your TPS by probing it with a DMM and slowly moving it back and forth, looking for dead spots.  I plan to replace my TPS this summer.
Title: High Idle???
Post by: dudeman351 on May 30, 2007, 07:31:29 PM
mine does it also. swaped iac and tps is .92v and it still does it. we adj the vam 3 clicks it helped but it still does it once in a while. i really think its a glitch in the la3 computer.