high idling low idling

CHEVROLET VAN
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TALBOTT
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I have a 1993 Chevy G30 Van with a 6.2 liter diesel engine, it just crossed over its 100,000 mile mark. We have been travelling in this van quite a lot driving long distances often. We started experiencing a problem on a cold morning not to long ago, I had the similar problem in the summer and after adding additive it halted until recently (an additive didn't work this time).

The problem is: I start up my engine to warm it up I let it idle for 5-10 minutes, Its starts in a slightly high idle and when its ready it drops to a lower idle. Lately its starts up fine and runs at a high idle then it will jump to a very very high idle (don't have an RPM gauge) sometimes it will fluctuate up and down everyonce in a while stalling and shutting off, but usually dropping to a normal idle and I leave. As we drive and it gets warm the problem becomes less and we forget about it until the next morning. Also when I drive it will surge in speed somtimes when barely pressing the gas and others will barely give me any power at all. I do have a coolent leak and fill that up every once in a while, I don't know if that is related.

I have read other threads similar, you've listed IAC, MAF, idle speed motor, could those apply to a diesel, Air? I have taken it to a mechanic and since it was warm they couldn't figure anything out.

Thank you for the help sorry for the length of the post.
Oct 19, 2007 at 10:54 PM
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2CARPRO JACK
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All those things could aply to your truck. Have the PCM scanned to see if it has stored any codes.This will help in figuring out what is wrong
Oct 20, 2007 at 8:06 AM