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6.0 No Power Misfires?


greasemykey

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You could always unplug the driver's o2 and unscrew it out of the exhaust, if the cat is partially clogged, the hole where the o2 was usually lets them run a little better. Also, while you're under there, make sure the fuel regulator isn't squirting fuel out of where the vacuum line connects to it; while it's running.

Edited by Mr. 3/4 ton SS (see edit history)
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You could always unplug the driver's o2 and unscrew it out of the exhaust, if the cat is partially clogged, the hole where the o2 was usually lets them run a little better. Also, while you're under there, make sure the fuel regulator isn't squirting fuel out of where the vacuum line connects to it; while it's running.

 

i dont see or smell any fuel under it. but it deffinitly runs rich. someone told me to put a pressure guage in the upstream O2 sensor and if i have positive pressure over 3psi then its a clogged cat. has anyone heard truth to that as well?

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Yeah, that's true. But, did you check the vacuum port on the fuel regulator? Sometimes the diaphragm cracks and lets more fuel into the intake, through the vacuum line.

http://www.youtube.com/watch?v=AKtR_yF7bi8&feature=related

http://www.youtube.com/watch?v=bwKM99P3LwM

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You say you hear a rattle, along with the other symptoms mentioned, I agree with Zippy that you most likely have a plugged cat. Seeing your mileage and the track record of the factory cats, it's almost a given. There is a simple test you can conduct that will save you anymore heartache........slide under the truck and wrap on both cats with a closed fist(when cool of course), if you hear a rattle, that means the cat is degrading and coming apart internally. Time to gut them, cut them out, or replace them......

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You say you hear a rattle, along with the other symptoms mentioned, I agree with Zippy that you most likely have a plugged cat. Seeing your mileage and the track record of the factory cats, it's almost a given. There is a simple test you can conduct that will save you anymore heartache........slide under the truck and wrap on both cats with a closed fist(when cool of course), if you hear a rattle, that means the cat is degrading and coming apart internally. Time to gut them, cut them out, or replace them......

 

 

thats weird the ones in my silverado are original with 240K on them. i guess i got lucky. i found one at AutoZone for 170 so im having it put in tomorrow. ill let you guys know what happens once the old one is cut out. thanks for all the help so far.

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im guessing that may explain the rattling sound i am hearing when i try and accelerate.

Just an FYI, depending on your years and mileage, the cats are covered under warranty for 8 years or 80000 miles. It's actually a federal law and gm does cover it. Just had mine replaced. I blew the cat apart.

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