# 06 gto losing high rpm power



## FATASSGOAT (Jan 30, 2012)

hello all, I have a friend with an 06 GTO with some mods (TSP tqer 2 cam, cai, etc) and recently he has been losing power in the upper rpms. It almost as if it is either stalling or missfiring...it gets a fast popping sound from the exhaust and can only climb past 5500ish slowly. Let me know where he should start...plugs? Maf?


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## 06BLACKGTO64 (Oct 30, 2010)

can you post a video of this?


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## ViperT4 (Jul 18, 2010)

Valve float? Did he change springs with the cam?


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## FATASSGOAT (Jan 30, 2012)

ViperT4 said:


> Valve float? Did he change springs with the cam?


Yes, beehive springs.
'll try to get a vid....it's currently raining so It'll be a little bit


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## billyjack2 (Oct 21, 2011)

Sounds like your ignition is failing to keep up with the demand on the top end. Easiest thing to check would be the plug wires and spark plugs. 
No codes I assume?

If all that is good, double check your grounds.


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## MarkMGTO (Jan 6, 2012)

Can anyone help. I have a 2006 GTO, shifts and responds very well, until after a short high way distance, the car feels like it is stuck at a speed usually around 60 mph, wiht very high RPMs, Unable to move beyond this speed. Pulling over to the side of the road, stoping and then resuming, car returns to normal. Has plenty of power, excellent shifting, smooth, until a few miles up, this problem will repeat itself. This was happening very intermitantly, at first. Before the problem worsened, I was on a long weekend trip. This problem occured the last hour of the drive. A local mechanic in town, looked at the car test drove it, and agreed it was not the transmission. he tested car at all speeds, even as high as 125mph. He said, car responded way too well for trany to be bad. He said it was one of the servos to the tranny. My mechanic at home, checked the car out, found it was the TCM that was bad, as evidenced by scanner failing to communicate with TCM, after 5 hours of diagnostics. The TCM was replaced, he also checked all servos in the process. They are fine. When I took the car back, it repeated the problem, Hitting the breaks I find usually corrects the problem. I brought the car back to him, and the car is not picking up any codes at all, the problem is not repeating itself for him. My check engine light has never gone on for this problem either. The car, has 120,000 miles on it. Trany fluid checked and normal, and the trany shifts beautiful for the most part, when this issue is not occuring. I hope some one has an idea. The mechanic checked with GM, they have not had any reports of this. He also felt it was a bad ground, however can not find anything.


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## svede1212 (Nov 1, 2005)

The only way to properly diagnose this problem is to log a run with a wideband and a tuning suite. It could be something as simple as a crappy tune (pretty common), drop in fuel pressure , too small of injectors or lots of things. Anything else is just guessing.


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## MarkMGTO (Jan 6, 2012)

svede1212 said:


> The only way to properly diagnose this problem is to log a run with a wideband and a tuning suite. It could be something as simple as a crappy tune (pretty common), drop in fuel pressure , too small of injectors or lots of things. Anything else is just guessing.


Hi what is a wide band and a tuning suite?? Sorry just have not heard of that before?


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## svede1212 (Nov 1, 2005)

I guess I'll try to better answer both questions.

A wideband controller is used in conjunction with a wideband O2 sensor and monitors your air/fuel ratio (AFR). When cruising your narrowband O2s (stock on the car) maintain the AFR at 14.7 parts of air by weight to 1 part gas. At wide open throttle the car needs to go richer to keep from blowing up the engine and providing more power. Generally that's in the range of 12.6-12.8 AFR on a NA engine. 


A tuning suite allows you to log a whole bunch of parameters of the car under actual driving conditions so you can see what's going on. It also gives you the ability to adjust hundreds of things including AFR and flash that into the car's computer. The factory tune has the WOT AFR very rich to give themselves a very wide safety margin. Just tuning the AFR correctly and raising the timing advance gives a nice bump in HP. With cams nailing the AFR and adjusting the timing is critical to stopping RPM surge. 

You can also monitor and adjust where the car shifts, shift pressures, cooling fan set points and a ton of things.


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