Car falls on its face off the line, how to set idle?
08-15-2007, 09:47 PM
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Car falls on its face off the line, how to set idle? Only had the car for about 2 weeks. Finally floored it off the line at a stop the other night and it stumbled, then turned the tires to smoke. WHat would be a common place to start looking for an off idle stumble? Also, are the TPS and IAC adjustable in these cars? I have a scantool, so its no problem, I just want to know what they should be set at, the car idles a bit high...
08-15-2007, 10:16 PM
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at idle. or with the key on engine off, your TPS voltage should be around a half a volt (.5v). When you floor it, the TPS should read close to 5volts.
Your IAC should be around 5-50counts. for GM they call for between 16-20 counts. If the IAC count is very high, this means that your throttle plate could be clogged or mis adjusted linkage. If its low, it could mean that you have a vaccum leak, maybe from your PCV or a hose thst broken
Your IAC should be around 5-50counts. for GM they call for between 16-20 counts. If the IAC count is very high, this means that your throttle plate could be clogged or mis adjusted linkage. If its low, it could mean that you have a vaccum leak, maybe from your PCV or a hose thst broken
08-15-2007, 10:22 PM
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Exaclty what I was looking for, thanks! Is there any special "procedure" for setting the two? Just asking because my Buicks only tend to take to the settings in a very specific manner, the fragile beasts they are...thanks again
08-15-2007, 10:27 PM
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the TPS and IAC are not adjustable. the TPS simply reads what position the throttle plate is at. The IAC (idle air control) is what controls your idle. its a small passage in the throttle body. You should give your throttle body a good look over and make sure theres no **** in there or anything 
08-16-2007, 08:15 PM
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I'm dealing with a stumble when I start sometimes, its an m6 so its only occasionally, but when I have the revs low and let the clutch out nice and smooth the car will lurch and then take off like the original poster described. I havent paid attention enough to see if it does it at WOT, but it is certainly annoying. I'm going to see how everything acts when I change the plugs and wires... have you tried that?
