Whats Wrong With My Yukon?

[roscoe1129]

Yes, that was parts and labor. I though about doing that or going with this

http://store.summitracing.com/partdetail.a...mp;autoview=sku

I know its not smog legal but the cats are in the stoc location as the ones on my yukon.

well if you have the means to do it yourself but there isnt that much of a difference in price id have a shop do it so you dont have to fuck with it and get a warrenty on parts and labor thats the way I would go

[mcnaught82]

Keep the old ones and turn them in for scrap. The have platinum in them and you can get about $80 each

Ill do that, thanks

[mcnaught82]

well if you have the means to do it yourself but there isnt that much of a difference in price id have a shop do it so you dont have to fuck with it and get a warrenty on parts and labor thats the way I would go

True, Ill probably have the shop do it.

[Dr. Johnson]

how many miles are on your vehicle? and it is gm correct?

[infkt]

I would check your header down pipe 02 sensor (the first one closest to the engine) mine did the same exact thing but mine was on a jeep i figured out that one of the wires had separated and cause it to malfunction horribly. before you just replace your cat unhook it and drive say around the block and see if you notice a difference.

[mcnaught82]

how many miles are on your vehicle? and it is gm correct?

Its a 2003 GMC Yukon XL 5.3L 123,000

[David]

Whats Wrong With My Yukon?

its a gm product

[Dr. Johnson]

Its a bummer you have so many miles, gm has to warranty cats for 80,000 miles. Good luck figuring this out it sounds like it is going to be a headache and expensive too. my .02 its the cats.

Edited October 25, 2008 by Dr. Johnson

[mcnaught82]

I talk to a mechanic lastnight and he said it is most likely the cats, and the knocking I hear from the motor is Spark Knock (Detonation). I hope I didn't fuck anything else up in the motor because of the detonation. I read that detonation can damage piston rings, rod bearings, head gaskets, and spark plugs. How can I tell if the piston rings are damage or the rod bearings?

[--Navi--]

I agree with cats like others, something else to check is the accordian boot from the air filter box going to the throttlebody. Its not uncommon for when these get aged to become weak and sometimes collapse restricting air flow. Mine did it about 6 months ago and was similar to what you mentioned of being able to rev freely in park or neutral, put it in gear and it would take off fine until it hit 35 or so and fall on its face. Originally thought it was the cats as well, pulled them at the collector and had the same problem so it ruled out the cats. Stumbled across the accordian boot while look at 02 sensors and it was the problem.