My 2001 Blazer has the same rough idle and a missfire indicated on #2 cylinder. Thinking it was an ignition problem I changed the plugs and wires, distributor cap and rotor, checked the ICM (it was fine), fuel filter, air filter, fuel injector for the #2 cyld, and the intake manifold gaskets while I was at it. It ran a little smoother, but still idled rough and had the missfire code. I finally traced it to a stuck exhaust valve. I have no compression in the #2 cylinder what so ever.

I can hold a piece of paper under the tailpipe and it will suck it upand then spit it back out. Thus, I'm pretty sure,is a valve problem. This might not be your problem, but it might be worth it to check it out. Hope this helps man, good luck.

-nimrodcs

 

not saying this is your problem either but did u check the valve springs mine jimmy was ding the same thing i put all new stuff in it and still didn't fix the problem came to find out the valve spring a $2 item was the problem with that many miles the springs r probably getting weak if they r not already

 

I was pleasantly suprised when I found a engine misfirewith my '91 Blazer 4x4 . It began aslight miss not long after my daughter had the battery replaced. The miss was onlynoticeable in top gear of the 4-speed automatic, especially on a slight grade.

It turnedout ot beslightly loose battery cables. I took1/2 turn on the side terminal bolts and later test drove the SUVand the miss was completely gone. I would have never thought that would cause a intermitten engine miss because I am used to 50s and60scars that can run fine without battery cables after you get them started.

Could loose battery cableshave been the cause of the engine miss orwas loose cablesjust acoincedence?