Hey guys anyone ever seen a plugged cat. Cause a lean o2 code? I'm working on a s10 blazer for a friend, after a long cruise, it looses power just like a bad cat, and set a lean o2 and multiple missfire code.

 

Have you checked or changed out the TPS? I had that problem changed out the Cat and no change. Changed O2 sensor also. Ran some test, said the TPS. So changed it out and bingo! But I also had a few plug wires that were chewed up, fixed those at the same time. What size motor is in the S10?

 

I didn't think of the tps, its a 95 4.3, but its an obd2 vortec. The ses is on, so ill look at the freeze frame data and see what the tps voltage is like. Thanks.

 

We had the inside tube(double tube style) of the exhaust Y pipe collapse on us. You couldn't tell anyting from the outside, but the inner tube was pinching off exhaust. It was found by an Auto Tech Teacher when he checked the vaccum of the engine.

Cars heat up on the freeways and when shut off quickly with out a cool off time, they begin to collapse.

Just throwing my experience in, this had us stumped for weeks!!! GOOD LUCK!

 

What was your vacuum reading? I'm getting about 5" at wot.

 

I had a plugged cat on another car, and it ran very weak. Don't know about codes.

 

Like steve said, it will cause severe power loss above idle

 

If you have 5" of vacuum at WOT, then you've got other problems. You should have 0" of vacuum at WOT. If your information is correct (and your gauge) you have a restriction in your intake.

A symptom of a clogged cat that is very quick/easy to diagnose is EXCESSIVE induction/intake noise at open throttle settings. Like the "good 'ol 4bbl sound"....but 10x louder.

 

the spider injectors are notorious for giving problems on those engines. might be something to look at if you cant find anything else.