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Recently my '92 Lumina 3.1L has been revving somewhat high upon start-up. This occurs somewhat rarely and usually when the engine has not been ran for a day or so. It seems that this stops after a few minutes of warm-up or a couple minutes of driving.
When the engine is started up, it sometimes revs higher than the typical idle while in park and neutral. This does not occur in R, overdrive, drive, 2nd or 1st gears(while moving or not).
It is fuel injected of course...but I'm thinking it may still have some kind of electronic choke. I really have no idea what would cause this since the oldest fuel injected engine I have experience with is my '96 VW VR6. Although, my '88 Ford F150 4.9L Straight-Six(FI) almost always requires to be warmed up before it idles normally.
If this isn't normal, I'm thinking I may have a intermittent vacuum leak or a throttle body sensor that is needing to be replaced soon. BTW...There has never been an engine light on in this car.
Thanks for any advice!
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Daily Driver: 1992 Chevrolet Lumina Sedan with 3.1L V6.
Other vehicles I own:
1996 VW Jetta GLX VR6. **Needs Transmission**
1988 Ford F150 4x4 4.9L Straight-Six.
Last edited by Dark Volker; 04-19-2009 at 05:02 PM.
Does this usually only occur while the engine is very cold? My doesn't do this very often at all.
__________________
Daily Driver: 1992 Chevrolet Lumina Sedan with 3.1L V6.
Other vehicles I own:
1996 VW Jetta GLX VR6. **Needs Transmission**
1988 Ford F150 4x4 4.9L Straight-Six.
You have what is called a cold engine mode. If you have a tachometer, you'll see that the engine will idle anywhere between 900 and 1200 RPMs while warming up. If its idling higher than that, its not normal. It should idle right at 1050 in CEM.
Cold Engine Mode should only occur when the coolant temperature is below 100F
And I have worked with mid 60's fuel-injected cars
It sounds to me like it is idling higher than 1200rpms when this happens. I don't have a tach though...not even one of those portable tachs that I can hook up under the hood to check rpms.
This also very rarely occurs. If the car enters CEM anytime that the coolant is below 100ºF, I would be getting these seemingly higher than normal idle revs a lot more often than I am.
__________________
Daily Driver: 1992 Chevrolet Lumina Sedan with 3.1L V6.
Other vehicles I own:
1996 VW Jetta GLX VR6. **Needs Transmission**
1988 Ford F150 4x4 4.9L Straight-Six.
It does not idle down after letting it warm up no matter how long I let it run.
The only way it idles down...at idle lol, is if I put it in gear and go somewhere. Sometimes when the idle is high like this, the car will die/stall when I put it into gear. If this happens I have to brake torque it a little when putting into gear to get moving.
__________________
Daily Driver: 1992 Chevrolet Lumina Sedan with 3.1L V6.
Other vehicles I own:
1996 VW Jetta GLX VR6. **Needs Transmission**
1988 Ford F150 4x4 4.9L Straight-Six.
High idle after start-up.
