Dyne was from 09. Nothing has been done to it since then. The kid I bought it off wasn't who built it. He said his buddy did. All receipts are from gm dealerships who installed all the upgrades so at least I know it was done right? Haha

 

I want to add that going through receipts i found that the cat was already replaced under warranty. Is it possible it could be clogged again? Or another restriction in the exhaust somewhere else?

 

The GMRS3 tune isnt a rich tune like GMS2, and isnt really known to clog cats.

Take the downpipe off and inspect the cat for yourself. No way for us to know unless you take a look at it.

 

Also if you take the pcm out of its plastic holder it should have a gm performance division sticker on the back, at least every stage 3 pcm ive seen has this sticker. But you probably have a clogged cat. Happened to me on an aftermarket downpipe that had a cheap thunderbolt cat and the actuall honeycomb interals broke apart and clogged the pipe. Nothing to do with the tune but with a defective part.

 

Alright man. And thats the thing I'm not sure is its gmrs3 or gms2. I have papers that said it was done but how can i tell for sure?

 

Good point ill look on the back. Have stock pcm too so I know its either gmrs3 or gms2.

 

If you have an adjustable rev limit and ability to switch to high octane mode, you have the gmrs3 pcm.

With the ignition on (car not running), press your foot on the accelerator pedal. If the rpm needle moves/climbs, you have an adjustable rev limiter.

If this is the case, you prob have GMRS3.

GMS2 uses the stock PCM. GMRS3 uses a separate/new PCM.

 

He probably doesnt even know about those functions yet, but that is another way to tell.

 

Now he does.

 

Yeah one of my buddies showed me the adjustable rev limiter on it when I first got it. I'll post a pic of the paperwork I have of the kit.

 

You have the GMRS3 PCM then for sure.

 

 

. I guess this explains why I have no ac haha.

 

Correct.

 

Well I'll remove down pipe this week. Have a lot of time since I already lost my license owning this car haha. If its not the cat any other ideas on what I should check?

 

Lol explain.

It's more than likely the cat, i've had multiples go out

 

84 in a 55. Too much fun haha. I've always had lifted trucks nothing I could go fast in haha.