Hey guys, first time using the forms here. Been trying to do as much research as i possibly can before diving into this problem. Anyways.. Its a 98' blazer lt, 4.3 v6,also has 160k miles on it. problem happened while going up a hill, it started to hesitate, and not rev over 2.5k rpms and almost caused me to not make it up the hill, huge lack of power. The check engine light came on, ran a computer on it got the code P0404, recirculation circuit range performance which showed that the egr valve could be bad, so i replaced it. (shelled out the few hundred for the new part and seals). Now the check engine light is currently off but the problem still remains.
A few weeks back i kept getting a o2 sensor code, but it randomly shut it self off and didn't return, im wondering if it could be coming back to haunt me, or could it be a plugged cat?.. I'm gonna check the plugs and MAF sensor tomorrow. Friend of mine told me it could be the MAP, but any advice on the trouble shooting would be awsome. I'll start by cleaning the MAF cause its easy to get to. But how do you test the MAP to make sure thats fine? Thanks a ton for your time guys

 

cat is a real possibility-actually put one on a 98 Saturday(with 90k on it). Pull the O2 sensor out forward of the cat(between the cat and engine-nearest the cat). Then drive it and see-if it's better....you need a cat. Jerry PS there are other things it could be but this test won't cost you anything but time and could prove alot![:-]

 

The very same symtoms happend to me. No power to pass, very sluggish, very poor towing. Then my blazer began to have issues starting. I had the fuel pressure checked and it was about 10-15lbs pressure under spec. I replaced fuel pump and she has more power and runs better than I can remember.

 

I also second what Dale says...A fuel pressure gauge would be another cheap test to do to verify! Jerry PS I would test both if the first test shows nothing out of whack[:-]

 

alright i'll give the first few things a test :-).. just wish it wasn't 0 degrees outside.. stupid Minnesota
*COMBINING CONSECUTIVE POSTS*
Update: Pulled the maf sensor.. looked brand new. Pulled the o2 sensor right before the cat, and it ran a heck of alot better, loud, but better. So i guess my next investment is a new cat and i might as well replace the burned up o2 sensor, cause it was completely covered in carbon. Also, there looked to be a bunch of condensation pouring out of where the o2 sensor was, had a faint gas smell to is. I'm just wondering what that could be from. It sat for about 3 weeks without running. So any input again would be amazing. Thanks guys

 

Update: Pulled the maf sensor.. looked brand new. Pulled the o2 sensor right before the cat, and it ran a heck of alot better, loud, but better. So i guess my next investment is a new cat and i might as well replace the burned up o2 sensor, cause it was completely covered in carbon. Also, there looked to be a bunch of condensation pouring out of where the o2 sensor was, had a faint gas smell to is. I'm just wondering what that could be from. It sat for about 3 weeks without running. So any input again would be amazing. Thanks guys