okay - idle has been set to 850 via a madz tune. if i start the car up it seems like its searching for the idle (reving slightly between 500-900) then after a few minutes finds it at 850 and idles great.

the problem is if i start driving for a few min. when i come up to a stop sign or just stop my idle now is between 1200 and 1400.. and will stay that way.

ive checked and cant find any vacum leaks - and have clean and reset the IAC but nothing has changed. could it be bad just a bad IAC? or anything else i should look at?

thnx

 

Try removing that airfoil. Stock TB? if so, try closing the throttle blade stop screw a bit.

 

^^ What he said.

 

okay - removed the airfoil- reset IAC and started car. idle was fine then when i gave it some gas settled at 1400.

so i messed with the set screw a bit. reset the IAC and idle would start perfect and about 15 secs later it would slowly bring it up to about 1400

leading me to believe the IAC is just crapping out... any other ideas?

 

My 97 started doing this about a week ago too, when I come to a stop the idle will sit at about 1200 RPM and wont come down. Sometimes if I give it a quick rev itll go down. I havent realy had a chance to look for any problems though.

 

same thing - if i give it a quick rev it will drop back down for a bit

 

I've seen some BBK throttle bodies do exactly that. Sooner or later we always track it down to the throttle plate sticking open just ever so slightly.

Stock TB?

Warm up your car and get it to act up. Then pop your hood and use your thumb on your throttle linkage to push it all the way shut. Did that fix your idle? If so, you have either a plate, or a cable problem...usually throttle plate on aftermarkets, usually carbon build up on stockers. Rarely cables on vehicals that don't go mud running (you don't, do you?).

If pushing it shut didn't solve your problem, you might have a bad IAC, but they don't fail often. I'd hook up a scanner, an see what the PCM is commanding the IAC to do. Are you sure that you arn't sucking fresh air somewhere? Intake manifold? - JM.

 

Mine does that now after my madz tune too. i figured that it was just to help the car warm up quicker because it only happens on mine before the car gets to 160*. So you guy are saying it is actually something wrong???

 

Yeah I have pretty much the same problem. I just spent over 80 dollars on a brand new TPS and IAC. I've been trying to fix this for a few weeks now.

 

YAY!!!!! finally fixed my idle issue.

basically i had gone through and tried everything.. and along each step found little problems hear and there-

1)found bad crack in a vacum tube... helped but not to an extent- idle would still stick high - but at least at start up idle was low-

2) adjusted throttle screw - once again helped out slightly just to start the car..use to need to give it a bit of gas to do

3) cleaned TB in and out- found the pintle on IAC was caked in carbon deposits, so cleaned off. found top gasket for TB plate was completely shot- deformed as hell, big tears and rips on the edges and even a corner missing. so replaced. improved a bit, instead of sticking around 16-1400 it only stuck around 1200..

i was holding out as a last resort to replace the IAC cause everyone had said they very rarely actually go and usually other problems. which i had been finding..

but finally cracked and bought the IAC - and idle is perfect now - she fires right up, idles almost on the dot 850, can drive it and rev it- put the clutch in or come to a stop and she instantly drops back down to 850

so... guess a lot of little problems, and the actual IAC were bad. man... at least my car will finally lope at a stop light now. although, the high idle helped add to the sleeper effect

good luck with your problems guys, all i can say is start with the small stuff and work your way up -ohh plus pulling the TB apart gave me an excuse to finally polish the thing to a mirror shine and get a new billet TB plate.

 

SPOKE TO SOON



after sitting for a bit - went out and started her up - idle sat at 1,100, then after reving it stuck at 1400 - only other thing i can think of are my TB blade bearings are bad and shes sticking -

guess ill be checking that after im done swapping the old IAC in- speaking of which if anyone wants it- its in the classifieds- only 5 miles on it- pictures included