Just bought a 2002 Blazer 4x4 with 140k. It has an issue with acceleration. when you push on the gas it feels sluggish and the engine is louder, but once it picks up speed the Blazer runs normal. From what i have read in other forums it seems like the same issue people have when their cat. gets plugged up. Only difference with mine is that there currently is no cat. on it. Can the missing cat cause the o2 sensors to read incorrect measurements causing lack of acceleration? Also could the muffler get plugged up like a cat can? Any help would be great. Thanks!

 

If the converter's insides break loose, guess where they go? Is that why you removed your cat?

 

I bought the blazer without a cat on it. so I am trying to put it back together properly as I go along. I am sure I will have many more questions to post in the near future as i come across things. It does make sense that the cat parts would get stuck in the muffler. Thanks for that idea.

 

Truthfully most of the cars i've seen run better with a cat on it. My truck is an example, someone sawed off the cat from the sales lot, and it ran like crap, new cat runs fine now.

 

Ok, so I changed the muffler but the problem is still there. I have noticed that it kinda feels like the engine either has too much air in the air/fuel mixture or not enough air. I also noticed that when shifting from 1st to 2nd then to 3rd the blazer feels sluggish, but once in third and the tachometer hits 4000 rpms the mixture feels perfect and the blazer runs great. But once I come to a complete stop and then go again the mixture doesn't seem right. Some times it will run fine out of first or second gear though. It is all random. But it does seem like the higher I get the RPMs, then the better the Blazer runs. Any other suggestions? All your help is great. I am not a mechanic so I hope my explanation makes sense to some one here.