my girl friend has a 2000 sunfire with the 2200 motor 4 speed auto. when we are going down a hill or of the gas just leting the car go on its own like down a hill or something, the rpms go all over the place. they will drop down to where the car almost stalls out, then jump back up past 1500 rpms, then it will keep doing that till we come to a full stop or hit the gas. any idea on whats makeing the car do this?

If it idles good when you're not rolling, I'd say it's in the transmission. Make sure the trans fluid is filled enough and doesn't smell burned.

If that's OK, try this test... When coasting, put the car in neutral. If the engine speed idles OK, then it's transmission related.



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John Wilken
2002 Cavalier
2.2 Vin code 4
Auto

i put the car in N when it was going down a hill and it still did it. it does it really bad at like 30mph if i let of the gas thats when it starts jumping around the most.

Unplug the IAC valve and run the car again. Is there any change?

2002 Cavalier 2200 5spd