Help!! I just bought a 2000 Somoma with a 2.2 , AT , 2 wheel drive and when you are holding a steady speed from 40 to 60 mph the rpm will jump up and down around 300 to 400 rpm. If I drive it over 60 mph it doesn't do it at all , and my code reader isn't giving me any codes when I check it. Has anyone out there had any similar problems and what was causing it. I would like to be able to fix this myself without having to spend a lot of time and money at the Chevy dealer any help would be greatly appreciated. Thanks Charlie
RPM surge
May 12, 2004
6 Replies
a fuel filter and a look at the throttle position sensor would be in order.
Is your AC running when this happens? This could be a normal RPM fluctuation when the compressor kicks on and off (remember, the compressor runs when you use the Defroster also). The other thing is to have your torque converter in your tranny looked at. If it's unlocking and locking back and forth that could also cause this.
Good luck - Jonathan
It probably is the TCC locking/unlocking because of a dirty fuel filter. Check that above all else.
~KJ/TLGM
======== Very good point Jonathan, it does have that lil' 4 banger in it......I drove one with an automatic once, it was so under powered it was dangerous :)
The Sonoma does have Overdrive but the transmission doesn't seem to be shifting back and forth it just seems to rev up about 300 or 400 RPM for just a second then it will drop back down to where it was. After looking at the many responses I think I will try the fuel filter first since it is easy and cheap and then go from there. I thank you all for your ideas it gives me a place to start looking.
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