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Questions and Answers

Chevy Blazer Problem?

Q. Vincent, I recently purchased a 1998 Chevy Blazer LS for my son when his 1991 Plymouth Grand Voyager was rear-ended and totaled. A strange fluctuation in the engine RPM occurs when driving steady, moderate speeds The Blazer has a V-6 (Vortec I think), with 2WD, Automatic, 80,000 miles, P/S, A/C and cruise.

Chevy Blazer Problem?

When driving at speeds between 30 and 50 mph, I notice the tachometer needle drift up and down 200 - 300 rpm, even though I'm holding the speed/gas at a constant rate. It does this whether or not the A/C is on. It doesn't seem to have any problems at higher speeds of 65 - 75 mph. It shifts fine, no slipping and it's relatively smooth.

When I first bought the SUV, I had a mechanic friend check it out. He said other than some minor body work done, the Blazer was in relatively good shape, but he did notice this floating RPM. He tried to hook it up to an analyzer but could not get the computer to connect for some reason.

He thought there could be a problem with the overdrive on the transmission, but wouldn't venture a guess without being able to get a complete analysis done. In your experience, do you think the problem is related to the transmission, or perhaps a computer/sensor controlling the transmission, fuel injector, or something else?

Regardless, is my son facing costly repairs? I haven't had my son take it into a Chevy Dealership yet because I want to narrow the cause of this down first. Like anyone, I want my child to have a safe, reliable vehicle when he's 250 miles from home, and when repairs are needed, I want them made correctly the first time and not have to return to the service area three or four times before the problem is finally solved. (In my opinion, multiple visits can be more stressful and aggravating than a high repair bill.)

One final question, since there are apt to be other problems with this Blazer before my son is done with it, could you recommend an on-line resource or news group that focuses on Chevy SUV'S?

Thanks in advance for any information you can provide.

A. Well, this site is pretty reliable for info on just about any vehicle. Personally, I would not worry about it. There may be nothing wrong except that someone lead you in a direction that there "may" be a problem. A 1998 Chevy Blazer has On Board Diagnostics II. If anything goes out of specs, it should turn on the check engine light and set a code. If there are codes set in memory, a dealer with a Tech 2 scan tool will be able to retrieve them which would aid in diagnosis.

Some Aftermarket scan tools are not compatible with the OBD-II system in a GM vehicle.

Additional Information provided courtesy of ALLDATA

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