My check engine light came on got it scanned and he said the codes were possible missfire bad o2 sensor and possibly a bad cat. I just got it inspected and the mechanic said he replaced my o2 sensor. Before I got it inspected it ran fine but now when im driving slow I feel a hesitation and I mash the gas it heistates then feels like it breaks free. I just replaced the spider on it replaced all the plugs cleaned my mass airflow sensor. What could be causing the hesitation and possible missfire code?

 

normally if one O2 sensor is going out, they all are. you should look into replacing all of them. expensive, yes, worth it? yes. the possibly bad cat could be caused by an O2 sensor that hasnt messed up enough to throw a DTC.
i have a question for you though, when you did this "throttle blade mod," did you completely remove the throttle blade? or did you take it out and put in a different one? i am curious.

 

I took the diffuser off of the blade its rivveted in origionaly so I just popped the rivvets but when I got it scanned it threw 5 codes so I put the diffuser back on and just put new rivvets in it so it looks like it used to. How many o2 sensors are on the 96 blazer? I read on some post people say 2 some say 4 but I want to know how many there really is because my mechanic sapposibly replaced the 1st o2 sensor. But I was thinking of pulling the cat off and cleaning it out and cleaning all the o2 sensors since I dont have more money to keep dumping into it.

 

I might just try and seafoam it or something to see if it helps I dont really want to keep replacing parts.

 

Also could the o2 sensor be causing the possible misfire?

 

i dont think that an O2 sensor could cause a mis-fire. they do make the computer adjust fuel ratio, but not that much, not enough to make it misfire. there should be at least 2 i think, but there could be 3. you just have to get under there and take a look. im not too sure on the 96 because it was the first year of the OBD II i believe. if its like mine, you have one on each bank, cylinders 1-3-5 and 2-4-6, and then you have one after the cat.
i dont think that there is a whole lot you can do about "cleaning" out a cat. unless you knock the guts out of it and then it will really start throwing codes. not to mention, its illegal pretty much everywhere.

 

have a 2000 Blazer 79000 original miles, engine light had come on and took truck to get inspected. was told the car failed due to code P0440 Evaporative Emissions...can anyone tell me what that is and how i can go abouts fixing problem so that my Blazer can pass inspction....thnks

 

Well I cleaned my distrubitor cap because it had carbon build up it fixed the cheack engine light for a few days and it just came back on today. I think it might need a new cap the wires are fine looking.