Hey y'all - I have a 1994 Chevy S10 Blazer 4x4 (vin: W) and been slamming my head into a wall trying to figure out an issue. When she starts up cold, she will drive pretty badly (explained later here) until I start to drive her (30 seconds) and she drives amazingly. Shifts perfectly, sounds great, good power.

After maybe 10/15 minutes of driving, she just loses all of her power. I hear the RPMs spinning high (no tach so can't tell) and I hear the engine "whine" plus a lot of what sounds like air under the hood. The sound and performance issues wont go away until she is cold again.

The symptoms seem a LOT like this forum post: https://blazerforum.com/forum/2nd-ge...rmed-up-79863/ which makes me lean towards a plugged cat/some exhaust issues, but I just took it to a muffler shop and the tech who has been "working on cars a long time" didn't think it was the cat, but the tranny being bad.

I'm at a loss of what to do - cat would be cheaper but I'm not sure if it will fix the issue. I'm not positive it's the tranny either.

Things I have replaced and checked:
Fuel pressure is good (had to replace fuel pump and filter)
Plugs, wires, MAP, PCV valve, TPS, thermostat, coolant temp sensor

There are no codes in the system either - anything I can do to drill down the actual problem?

 

To anyone reading this in the future - physically remove the oxygen sensor off the exhaust manifold and drive. It will reduce the backpressure.

If the car runs better, you can bet it's the cat that's messed up.

 

Wow --- an active zombie thread!

I'd run a pressure test on the transmission first - that way, you can eliminate a lot of nightmares about needing it to be rebuilt.

Gauges, meters, and scanners are where it's at now.