Ive got the exact same problem as Saraegan. 2001 Isuzu Rodeo, 3.2L, 2WD, 85,000 miles.
Basically, when I start it after it has been sitting for awhile (atleast 8 hours) it runs well for about 5 seconds then starts reving up (to 2500 rpm) and down (to 400 RPM). Sometimes on the low end it drops far enough to kill the engine. Regardeless of whether I let it sit and idle or not, when I begin driving the car "surges" alot and becomes very unpredictable. In terms of power (it never had much to begin with!), It has been gradually degrading for about 2 years now. I have to basically floor it (without exageration) in order to pass someone on the highway.
Here is what Ive done so far: fuel treatments, replaced oil, oil filter and air filter, and I had an O2 sensor replaced about 6 months ago. I left it with a mechanic friend of mine who had his computer hooked up to it while I started the engine. He couldnt pinpoint anything other than unusual readings from the O2 sensor.
Would a tune up be the next step? I had one done at 50k miles. Ive heard many other suggestions dbut nothing concrete: EGR valve, PC valve, MAS, etc. Any help you guys can provide would be much appreciated. At this point the car is getting to be undrivable and no one can figure it out (even the dealership).
Thursday, August 9th, 2007 AT 1:31 PM