Chevrolet Blazer

Hi, I have a 1998, Chevy, Blazer, 4x2, 4.3 engine, with 125, 000 miles on it. The engine is original. I just got a tune-up because of this idiling or reving noise that I have been hearing for the last month. It sounds like the engine won't go into gear after accelerating from a stationary position. It almost sounds like if I was driving a stick shift that sound it makes if you don't switch from 1 to 2. Once the car gets up to about 30-35, I hear what sounds like it hasn't switched gears or something and it is just reving. I also, about 2 months ago, had a fuel pump installed and I didn't hear that problem before or after it was installed. I got the tune-up and the sound hasn't changed. I didn't get a major tune-up, they changed the spark plugs, the wires, the air filter but not the oil filter. Please tell me what could it be because, I don't want my engine to go out on me. Could it be the oil? Or the belts? Or their are too many miles on it.
January 23, 2007.

You might want to check the egr valve if its sticking then there is to much carbon in it. So it needs to be cleaned. We had this problem on a 95 blazer and it worked great, just have the codes checked too. Just to be sure.

Feb 25, 2007.
I have this same problem, although mine started after the dealer upgraded my computer chip. ANyway, what and where is the egr valve? What do you use to clean it?

Aug 17, 2007.
You can clean the egr valve with the same thing you clean the trottle body. It can be bought at most any auto stores. It would not hurt if you Clean the throttle body also.

Aug 17, 2007.