Are you positive you don't have an exhaust leak before the O2? I thought for sure just an O2 would fix the problem. Pull the codes before you reset the ecu. Have patience, we'll figure this out.

 

I thought it would too. It fixed mine and we had the same symptoms.

 

I do have an exhaust leak before the o2. A manifold stud is missing

 

Oh lord. Fix that leak! An exhaust leak lets extra oxygen into the exhaust and makes the computer think the truck is running lean. It then adds more fuel to try and compensate, but it can't do the job. It starts running bad once the exhaust gets hot and the metal expands, letting more air in. Fix the leak, and it will start running right.

Changing the O2 was definitely not a bad thing, so you didn't waste your money. As they get older, they stop working as efficiently.

 

Dealership has these usually in stock, maybe 2$ for the proper stud and nut. If you're luck it's completely missing and you can just put the new one in. If your not so lucky you'll need a whole new set of nuts and maybe a new gasket. Check with the dealer about thier return policy and be prepared to do all the studs and gasket.

 

I have a 93 pickup 2WD, and i have somewhat the same problem where when my truck is between being cold, and warmed up. it will bog down and not be responive unless i put it to the floor. but once it warmes up all the way, it goes back to running normally. it also occasionally on and off will throw the check engine light, with code 25. (lean fuel mixture). do you think that replacing the o2 would solve this? or is it possibly something else?

 

Do the voltage and resistence checks at the ECM. This is the fastest way to check all the relevent sensors.
http://personal.utulsa.edu/~nathan-b...27troubles.pdf
Voltage values are on Eg1-124
Or
http://personal.utulsa.edu/~nathan-b...ne/44engin.pdf

if all the sensors are correct, it could be a sticky or cloged injector, lack of fuel pressure(Cloged filters, or bad pump or regulator).

Oxygen sensor tests are
http://personal.utulsa.edu/~nathan-b...42oxygense.pdf

 

If it hasn't been replaced in a while, it wouldn't hurt. Mine would only throw a cel only when I was driving down the interstate for a while and when I let off the throttle it would go off.

 

Thanks, ill have to do that. I also found a small exhaust leak just after the manifold so im going to get that fixed up and see if that helps.

 

Sorry for neglecting! But I fixed the problem awhile ago, turns out it was a bad TPS for me! Runs like a Toyota should(: However, I created a mean vacuum leak in the process (gasket didn't seal right) so I have to fix that har har.

Thanks for the help fellow runnerlovers((: