hey guys, its been a while, I bought a truck last year and passed on the ol '96 SSE to my little brother for school. well at 260k she'* starting to show her age.

Whenever you drive the car it runs great until about 3000 rpm and then it has no power and just sputters out. but you can drive the car fine if you keep it at around 1/4 throttle just fine. I haven't really used the forums for a while because i bought an OBD II reader for it and can usually diagnose the problems very easily, but I am not getting any engine codes whatsoever so I am not sure what the problem is.

You guys haven't let me down yet so I thought I would toss it out there before i retire the old girl, because she still looks great and up until now ran like a champ.

a little history on the car, a few years back the upper intake plenum failed and dumped all of my coolant into the motor all the way to the tailpipes. i fixed it myself and then it ran fine, but it occasionally leaked a little coolant now and then which was expected from me after having the motor apart down to the heads.

well my theory is that my cat is plugged a bit and now once the motor hits 3 grand the exhaust has no place left to go and the car runs rough. but i wanted to check with you guys before i rip off the exhaust.

any advice you guys could provide or any other things i may have left out just let me know,

-Jay

I would suspect the cat being plugged. You can also try testing the TPS, but I would lean more towards the cat.

thanks for the fast response. I was thinking about removing the O2 sensor to see if it runs better with a little more breathing room. do you think that would help?

That'* how you test a clogged cat. It'* going be loud.