Hey. I just been doing lot of tune up and replaced parts on my Blazer. It has problem with overheat with fuel pump over summer. Did replaced new MAP Sensor, Dist. cap and base, Engine temp. sensor, new intake mainfold gasket (I still have the header gasket, but havent install it yet). Thought those all would resolve the fuel pump issues, Nope. Just replaced new pump to stop the overheat. Which now im going stay above 1/4 of gas, hope it will not short the life of pump.. However. It been about year that is annoying me and my wife is the idling. It would make "light rough idle". It drive, run fine. So what would it be? No code set. Should I replace the header gasket? (there is no leak that I see of, or oil/coolant mix). I did replace new spark plug and wires last year summer, was not bad til recently last winter, it start doing it more now. What do you think that cause "light rough idle"? Would it be the whole Distributor assy.? Help me, that will be great, I've spend lot enough money on parts replacing on it. Additional info is that the rpm stay steady even idle is little rough, doesnt going up n down u know. i replace new MAF 2 years ago when i had other old fuel pump problem. Let me know. Thanks

 

What are you driving?

 

im driving 1998 Blazer 4WD. I also forgot to menton that I did also replaced new fuel regulator. Hope you can find the problems idea for me to do.

 

Did anyone ever have an answer to this? I have a 'light rough idle' as well, from about 500 to 1500 rpms it's kinda rough. but smooths right out once you pass 1500. Have a 97 and did a full tune up last summer but never fixed the problem

 

Bang the egr valve hard a couple of times with a hammer and rachet extension. If it clears up take her out and clean, replace with new screen type gasket.

 

FYP.. careful there.
Good advice.. wonder why these crud up so much.

ALSO.. plugs. If you are running any other plugs OTHER than AC Delco or NGK {makes the AC D} specified. And at proper gap.. Replace 'em. If they arent the problem now, they probably will be later.