Is your engine capable of free reving over the 3 grand mark? Have you tried to manually shift the transmission into a gear and hold it longer? I am not by any means saying your cat is ok, because it probably needs some attention, but it could be your TV cable out of whack or something internal in the transmission making it shift early and not hold on to gears.

 

+1 on the TV cable adjustment, seafoam, cat, and maybe throw in some new O2 sensors. Mine will shift @ 4500rpm 1-2 from a dead stop.

 

I have the new O2 sensor installed (only 1 to install), new cat is in the works, and seafoam is in possession. I read on some older posts that it's a good idea to get the dealership pcv valve for correct flow etc...when doing the plenum I bought a new one from napa before reading that, so now I'll get one from the dealer to be on the safe side, they're real cheap. I figure I'll get the new cat on there first, then adjust the cable if its needed after that.

and yes it is capable of revving higher than 3000 in nuetral or park

 

If it is revving without a load on the engine I would think you have more of an issue with the transmission than the cat. I mean it is never a bad thing to install a new one, but adjusting that TV cable could solve a lot of what is going on. Good luck on the fix. Hope it comes together.

 

Little update: Got a new cat installed on saturday and I'm here to tell you, that made a big difference. It feels like it has more get up and go and it changed the sound of my exhaust to an even deeper throaty sound thorughtout the rpms. the rpm revving issue still exists but is slightly better. Going to adjust that cable soon, it looked like it had a bit of slack when I peeked at it.

 

May sound like a stupid question, but did you make sure your throttle cable at the throttle body is in the proper channel and has full range of movement? Sometimes its easy to forget & have the throttle cable itself go above the channel and lock the tb at partial throttle> Always have to make sure the accelerator cable rides under the plastic channel and does not sit above it resricting its movement.

 

thats not a bad thought, but I took diligent pictures of the tear down and got everything back the way it was, but that's not to say it wasn't messed up from before...I'll take a look at that

 

Have an update here for you and a new related question. I've since the last post adjusted the tv cable to my comfortable likings, but it still wants to shift too early, especially when pulling the boat, but not as early as before. I'm hesitant to adjust the cable more for reasons of hurting the trans at some point and throwing bills at it when I don't have bills to throw. With that said, can a bad TPS play a role in the shifting too early? It seems logical to me if the tps thinks it's in one position but in reality it's actually in another? I don't know much about the tps sensor so I'm just spit balling here. Thanks guys.

 

Pull it a tad more to the rear and see what happens.

 

I had the same problem while in drive. Cleaning the entire PCV system worked, including the breather.