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2004 Chevrolet Colorado 1SB LS Z85 Crew Cab 126.0 WB

2004 Chevrolet Colorado
Trim Info:
Rear Wheel Drive, Crew Cab
20 mpg city / 27 mpg hwy
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January 29, 2010, 7:17 am

Mattt K

Question: Think the cat on my header is bad. How would i definitely know?

mechanic says its bad. very expensive to fix. changed the oxygen sensor myself and that was not the problem. when truck is at idle in park it will idle at 750 rpms and when you hit the accelerator rpms go up when but it comes down it almost shuts off and hits about 400 rpms. another mechanic said i needed my fuel injectors flushed and cleaned. which direction should i go

February 1, 2010, 3:27 pm

Ron W
Expert Mechanic

Pull your O2 sensor out again, and start the engine. DON"T DRIVE ANYWHERE because you now have a fire hazard. If you have power without it in , most likely your exhaust is plugged. Which usually means a bad cat. Put the O2 back in and go to a muffler shop. Most Muffler shops will do a back pressure test on the exhaust for you for free to verify the restriction. Or if it will run good enough, just go to the muffler shop first. Won't even have to get your hands dirty that way.

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