I have a 2002 GTP that cuts in and out at about 122 mph. I am at a loss as to what is causing it. For mods, I have a cold air induction, Autolite 104 spark plugs gapped at .060, DHP Ver 1 PCM, and a 3.4 pulley. For exhaust, I have a Catco high flow cat convertor, u-bend and resonator were replaced with straight pipe, along with 2 Flowmaster 40 series mufflers. The only pipe that is 2 1/2 is the U-bend/resonator replacement. The rest of it is stock piping. It starts cutting out at around 123. Before I installed the pulley, it would cut out at 123 then stopped after installing the plugs, but wouldn't hit any higher speeds. Once in a while I would be able to hit 129. After installing the pulley, it is cutting out at 123 again and will not go any higher. I do have an enhanced Autotap if it will help any. If I am correct, wouldn't I have a SES light if I had a true knock retard? I'm at a loss on this one. Thanks
2002 GTP cutting out
Jan 09, 2005
8 Replies
Same question as last time: Is it speed related or rpm related?
the car is at 4000 rpm at 123 mph
Is that 3rd or 4th gear on the 4T60E or 4T65E? What happens when you run it at 5000-6000 rpm in:
1st 2nd 3rd ?
That's as fast as your car can go. Bob K
Maybe you should try asking on the forum at glubgp.com Someone there might know.
Jay S
Thats where the speed limiter kicks in, you need to get a reprogrammed ECU.
Got a cardomain site? I wanna see the car.
For mods, , DHP Ver 1 PCM,
He's got a Digital Horsepower PCM. The speed limiter is removed with their programmed replacement PCM.
Jay S
hmmmmm, mine don't cut out until it gets to 129 and it's stock.....and it would keep going a long way beyond that if it didn't shut off at that speed (ECM/tire limits issue). It's still pulling hard at 129.
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