Pontiac G8 GXP...NEED HELP!

[STV-R33D]

I posted this over on the G8 forums with little luck so maybe someone here had a similar issue?

GXP is acting weird, it has a dead spot at low rpm...barely moves then takes off like crazy. If I floor it from a dead stop it only gets up to about 10mph until it hits 2800rpm then you can feel it ready to launch but it takes almost 3 seconds to get there.

If I power brake, it will only rev to 1300rpm and it just sits there at WOT, won't rev any higher...weird!!!

When I got the car it would jerk your head off during city stop and go driving so I had a guy try to tune that out of it, he got rid of the neck snapping take off but created the dead spot so I took it to the dealer and they over wrote his tune with the latest stock tune but it's really not much better. I think they put the tune for a Chevy volt in it? They gave me paperwork from GM that says the hesitation is normal but that is a .7 second delay, I have a 3 sec delay. The car revs like normal in park???

Dealer used a tester and said they can lock and unlock the torque converter so they said that's fine??? Dealer has no idea whats wrong?

GXP is stone stock

[BMR Sales]

Post the question over at Ls1Tech - they will probably help you

[GBNL]

Throttle body or connector maybe?

[srh3trinity]

IAC or check the fuel pressure at the rail.

[STV-R33D]

It seems to be in the drivetrain, once your rolling at speed it has power. I pulled the air intake apart and it was pretty clean. Wiped out the TB and even changed plugs. Its so weird to mash the throttle on a 400+hp car and have it almost do nothing until it's 50ft down the road.

[aussietony]

Sounds to me like its a pedal problem. There is two sensors in the fbw pedal assembly. I suspect you may have a issue there.

[cpd004]

Might be a traction control issue. I have a G8 and it almost sounds like the traction control hasn't been fully defeated. If you're sure you've turned the traction control off before hitting the gas to the floor, then their may be an issue with it not fully disengaging.

[STV-R33D]

Sounds to me like its a pedal problem. There is two sensors in the fbw pedal assembly. I suspect you may have a issue there.

That's what I thought but when the car is in park it rev's normally. It's revs with no delay and to the moon but put it in gear and that's when it does what it does.

I did turn off traction control...no difference.

I think I'm going to stick my neck out and have the torque converter replaced. The car is just out of warranty but if it fixes it I will fight GM on it as I did take it in last fall and complained about it having shifting issues. BTW this car does have 98K miles on it.

[MonzaRacer]

I am fairly sure the "tune" in stock form is doing what it supposed to do, protect the weak link, the trans. I dont have access to check but if it has throttle by wire its all in the pcm control. YES you can buy a looser converter and get a better launch, and break other parts. To defeat traction control completely add a toggle switch to one of the ABS wheel speed sensor wires or find powers or grounds of EBCM and default it out completely, see if that helps. But my take is your seeing what stock is all about. As for tuning the computer, why not buy a setup too tune it your self.I believe HPTuners has way and lets you do one car per license or something. Bad thing about G8 is there is so much networked adding a different trans controller like the Megaquirt GPIO set up makes it hard.
Also dont forget the factory tach isnt THAT accurate.