I have a 1998 Blazer LS, with a Vortec 4.3 Liter engine. Three weeks ago, after replacing the AC compressor and accumulator, I was taking the family out to a local mall. While climbing a rather steep hill, the Check Engine light started blinking. After cresting the hill(while I was looking for a safe place to pull over), the Blazer began losing power and running very roughly. I soon got off the road and ended up having the Blazer towed in to my local mechanic, who diagnosed the error codes 'Multiple Random Misfires' in the #1 and #2 cylinders. Compression and fuel pressure are both good.

Since then, he has replaced the spark plugs, wires, distributor cap, and the spider injector assembly itself, but the two cylinders are still misfiring badly. He's trying out a new computer this week, but after that he says that he is stumped.

What else could be the problem here? I've put a lot of work into the Blazer this spring and would hate to send it to the junk yard now because of something like this.

Any ideas or suggestions are appreciated.

 

Are you wanting to do the work yourself, or are you looking to have the work done? If you want it done for you, you definitely need a different mechanic as yours is using the S.W.A.G system of diagnosis. If you want to do it yourself and are committed to obtaining an OBD2 scanner and any required tools, let us know and we will help.

 

Yeah, if the computer is not the problem, then yeah, I'm going to have to do it myself since I can't afford to take it to a fancy dealership shop.

 

That's why we are here. Helping you diagnose a misfire through forum posts can be quite a bit of effort on our part, so when you are commited to fixing it yourself let us know. When you come back please describe your mechanical experience so we can judge how much we need to explain.

 

I agree with Les 100%. As for replacing the PCM: It's extremely doubtful that is the problem. They are nearly bulletproof and rarely fail. Usually shops recommend them when they can't figure the problem out, with hopes of scareing the customer away due to the cost involved.