SilverSS07

iTrader: (1)

Hey guys. My 1995 TA M6 occasionally idles too fast. Maybe once or twice a month at the most. When it does it won't come down below 1100 or 1000 rpm. Normally it idles fine at around 800 rpm. I was driving around with the scanner in the car and it started idling around 1000 rpm. I looked at it and the only thing I noticed different was it showed that the throttle angle was 1%. Shut the car off for a few minutes and started it back up and then it showed throttle angle @ 0% and it was idling fine again at 800. TPS voltage is .58v regardless of throttle angle. Any ideas?

BALLSS

VDC should change from .67 vdc closed to 4.5 vdc full open with a "smooth" increase as you open throttle. Your TPS is bad or wiring if it just stays at .58 regardless of throttle position

your IAC could also be dirty/bad...but the vdc thing is not right on the TPS

SilverSS07

iTrader: (1)

Sorry I meant the tps voltage is the same whether it is idling at 800 or 1000. It does increase like it's supposed to. I cleaned the iac and put in a spare one I had with no change a few months ago.

BALLSS

vacuum leak will cause high idle...check for those

SilverSS07

iTrader: (1)

Thanks yes I've checked all vacuum lines a few times. I would think if it was a vacuum line that it wouldn't do it occasionally though. I'm wondering if somehow the throttle blades are hanging up sometimes. It's hard to diagnose though because it doesn't do it all the time. It hasn't idled too fast at all in a few days now.

cchvyd28

iTrader: (2)

Does it seem to do it more after you go wide open throttle? I had a similar issue except it would idle even higher. Turned out the throttle cable bracket behind the brake booster on the fire wall was bent and sometimes hanging the throttle open just a tad.

SilverSS07

iTrader: (1)

No doesn't seem to have anything to do with it. I hardly ever go WOT. Drive like an old lady most of the time lol. I moved the TB manually back and forth and sprayed a little bit of WD40 where the spring is. I traced the cable back to the firewall but didn't see any bends/kinks/chafing or anything. Does anybody know how throttle angle is determined? The last time it was idling fast it showed throttle angle at 1% instead of 0.

BALLSS

your IAC (idle air control) valve may be sticking or going bad.

Pull TB and them pull IAC and use TB cleaner and spray IAC valve clean and also spray clean the TB and re-install. You will need a new TB gasket

also do not push or pull printle of IAC or it will break

if IAC is sticking and holding a higher idle than the TPS would show a "x%" higher vdc as a result which may explain the 1% vdc reading you are seeing

SilverSS07

iTrader: (1)

When the car was idling fast the tps voltage was .58v and the throttle angle showed 1%. When the car idles normal it showed .58v and 0% throttle angle. Any idea why it would show the same TPS voltage but different throttle angle? I don't know how it determines throttle angle. I have a spare IAC from another vehicle and I've switched them before with no difference. I checked the IAC counts before and they are normal. So far since spraying it with WD40 it hasn't done it again- but it would usually happen 1 or 2 times a month at most. I'm keeping the scanner in the car so when it happens again I can see if I notice anything else that's not normal.

BALLSS

well maybe your TB just was binding some from the spring/linkage area if WD 40 seems to have resolved

you have a stock or aftermarket TB?

SilverSS07

iTrader: (1)

Stock TB. Not sure if that fixed it or not. Won't know unless it doesn't idle fast for a month or 2. Intermittent issues suck.