I forget about that 3rd cat.. I do feel like a plugged. exhaust would cause some of these issues. still seems weird it eats cats thou.
what airbox do you have on it?
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
I forget about that 3rd cat.. I do feel like a plugged. exhaust would cause some of these issues. still seems weird it eats cats thou.
what airbox do you have on it?
Grady_Wilson
Supporting Member
Luckily for me, if one of my cats gets clogged, I can just straight pipe the sucker and be done with it. 
I talked to the mufler shop we might just gut that one out since it has no sensor anyway.Luckily for me, if one of my cats gets clogged, I can just straight pipe the sucker and be done with it.
i guess these trucks should only have 2.5, mine has 5 and 10 at throttle, according to what I was told over the phone
Last edited:
I know of another gmt900 that has tapped worse than my silverado did for years, i see it parked at the flea market the guy runs every week just haven't talked to him in a while.
It's a white tahoe probably a 07, He also runs a car show about once a month and he has some nice rides but still drives that tahoe around tappity tap tap. lol
see that makes me think yours isn't running badly over a slight little valve train noise. I didn't think about the plugged 3rd cat but since you've fouled out front cats before, I guess it's possible and would definitely explain it
gooffeyguy
Tom
You can say that now, lolLuckily for me, if one of my cats gets clogged, I can just straight pipe the sucker and be done with it.
Grady_Wilson
Supporting Member
Precisely.
A few months ago I would have been struggling to find a replacement cat that was CARB compliant.
if you pulled it, knocked the inside out and put it back on. is that something Cali would be able to tell was done?
Grady_Wilson
Supporting Member
Not likely since they would only plug into the car into the machine and see if there are any codes and to see if the system has passed all of its checks.
They do a visual check but no more sniff test, a sniff test should have given it away but not always.
I had a car that did not have a second cat, bought it that way and didn't notice until after a smog check, and it passed the sniff test.
I am going to be suprised if it is just that 3rd cat, the dealer here has some good techs but they want it to be stock, hence the request to re-install the factory air box and have the exhaust to spec. I think it is more for getting the readings needed to pin down the root problem. But w'ell see I have to go in my storage room for the airbox it's probably buried behind 7 years of junk i don't toss any of that stuff I always just stash it away, just for stupid reasons like this.
It's Somewhere in the abyss......
It's Somewhere in the abyss......
