[TX08manualGXP]

On my GXP, I've noticed that if i get on it in 1st and bring it up to and over 4500, when I depress the clutch and let off the gas, my engine is very slow to come back down towards idle. it only does it in 1st but pretty much does it all the time. when I'm in 2nd, and go above 4500 it seems like the RPM's come down a whole lot faster. I've also revved it up in neutral and some times it almost seems like it hangs there for a second. Any ideas?
It's been like this maybe since I got it but since I've been trying to figure out the power band, I'm noticing it more. I can be in 2nd or 3rd at half pedal, moderatly accellerating and the second I hit 4000, I get a boost of power like someone hit the nitrous button. is that part of the stock tune? i thought the granny mode was set for more like 3000 or 3500.

car seems to run fine and no codes.

 

[rob the elder]

The normal power characteristics of the turbo motors is for power to build relatively slowly until the turbo spins up. On my cars that was a process that did not start until around 2500 RPM and by 4000 RPM the turbo was working hard. It is a big change in power output.

The lack of return to idle is a different issue. I would check for leaks, clean the MAF and maybe look at cleaning the throttle body. While I have not had that particular issue, similar occurances have been described by others that have been a result of a sticking throttle body.

 

[TX08manualGXP]

I did read one post where someone was installing a new CAI and cleaned the TB while they were in there and had a similar problem but mine seemed to be different. especially since it was only in neutral or 1st. I think it's time for a new air filter too and was debating getting a cai or modding my airbox and or dropping in a K&N. I'll move that to the top of the list and go ahead and clean everything while I'm at it.

The turbo thing is weird because you can be slowly building up speed and the second it hits 4000, it almost breaks the tires loose. maybe once I get a tune that will cure that. I have checked all the clamps and everything seems tight. I even tightened the ones up front which were a total pita to get to. used a 1/4" ratchet, socket and 1/4" bit. all were rather tight to begin with though.

 

[The_Ghost]

First off, your "rev limiter" should stop the revs at about 3500rpm, if you are at a complete stop, no matter what gear your in. If you're moving even the slightest bit, it will allow you to go past that when you rev the engine. It will allow you to rev all the way to redline if you are moving any little bit. It is a built in protector to protect the engine from spinning past a certain rpm with no load.

That said, you need to be more precise. Are you in gear, revving to 4500rpm and letting the engine brake the car? Or are you revving the engine in neutral? Please be more precise....

My car breaks tires loose at about 3000rpm in 2nd, 4500rpm in 3rd

 

[LatinVenom]

Forget the K&N it will give you more troubles in the long run.
The stock intake manifold is excellent, just get a new air filter if the one there now is dirty.

 

[TX08manualGXP]

Ghost, I mean I'm driving in 1st, take it up to 5k and clutch / let off the gas and go to shift . Or if I let off the gas and clutch in, it hangs at a high rpm and takes a couple seconds for the RPM's to drop back down. I never let the engine tranny slow the engine. with my little trips, I do the above and can pretty much coast to the next stop sign but my engine is still at higher RPM's. On the longer stretch of road, if I do the same exact thing in second, it seemd the RPM's drop the instant I let off the gas and push in the clutch.