Quote:
Originally Posted by dadooishome
Got a 2004 Aveo last summer with 61k miles. Did the timing belt kit and tune up so it ran fine. Then it started randomly idling at 2200 rpm. Bought a new Idle Air Control (IAC) unit and it worked fine... for a few days, then the idle went to 3000. Disconnected the Throttle Position Sensor (TPS), it ran normal a couple days... then back to 3000. Decided it might be getting too much air from the EGR, so I disconnected the entire EGR (and plugged the ends) and it ran normal. So I put in a used EGR..., but it made no difference.
If I goose the throttle to 4000 then hold the butterfly closed, the idle drops down to 1100 for a second, then bounces back to 3000. Where is it getting all that extra air? In gears 3-5 under load it will only pull 2200 rpm, but when I put in the clutch.... 3000. So I just can't drive it.
The problem does seem somewhat temperature related because after an hour or so it sometimes does drop down to 1200 which is still too high.
I am completely baffled by this thing.  The only OBDII code is the ''engine rpm does not match throttle position". How can it get that much air behind the throttle butterfly with the electrical connections for the: IAC, TPS, and EGR all disconnected? HELP! |
with the throttle plate closed and 3K RPM there must be a vacuum leak.
use a vacuum gauge and with this taped into the intake see if you can make the gauge react by using propane to locate the leak... this set up is using a small torch with a 4 ft hose on the tip open the valve so just a small amount of propane comes out.. then use the hose tip/end to probe for leaks... you will see the vacuum and rpm shift when the gas enters the engine ... too much gas will make it harder to find leaks.
this is the best method than using spray products//safer..