no power above about 3000 rpms

[teslaman24601]

so i finally got my gtv6 running, yay confetti may now fall from the heavens. but like many cars, it still has some problems. I noticed that either hot or cold, (i try not to when its cold though) it has a hard time revving above 3k rpms. It still gets up to 6k, but as soon as the 3k range hits, it becomes drastically slower to rev. WHen i try to drive the car, its the same deal, up to 3k its fine, but when i get there, it doesn't have enough power to even accelerate the car at all, i have to shift up. Any ideas on what can cause this. i have gone through greg gordons procedure already and while very helpful, did not help me isolate the problem. If you need any more information or have any tests for me to run, i will do them and post the results to help better find the problem.

[Seattle Dan]

First - I'm not a GTV6 expert, or even novice, but I've had a mid 80's Benz that exhibited this exact problem once the catlytic converters plugged up. In my case, the cars burned a little oil (1 quart every 2K miles or so). I was told this is the kiss of death to the catalytic converter - it eventually plugged up and became very restrictive. This happened almost at 3000 RPM. If I downshifted, the torque of the motor at speed drove the RPM's higher, but without any power. Sounds very similiar - so if not the converter, then maybe some sort of exhaust restriction?

[ToonRboy]

Bad injector/s

[jontg428]

Possibly a stuck vacum advance unit?

[teslaman24601]

well, i cut the cat off and that seemed to help a lot, there is some more power, but its still not what i know it could be. i know the injectors are good, i bought all new injectors. is that the vacuum advance unit on the distributer? how do i check that?

[Giorgio68]

Check your AFM, sometimes the plug wires on the AFM gets loose.


Giorgio

[teslaman24601]

it is also running fairly rich and backfires when you let up off the gas. dont know if that helps

[mkeith]

Start with the basics. Check your plugs, wires, cap, rotor, & ignition timing. I once worked on a GTV6 that would not rev above 4500. It acted like it was hitting the rev limiter at that engine speed. Turned out to be the plug wires. They had infinite resistance.

[teslaman24601]

well, i know i am going to need some new plug wires as well, but this weeks gold star goes to jontg428. My vacuum advance itself was fine, but i noticed that it was not getting a vacuum at high rev. I went out and got a bottle of carb cleaner and sprayed it into the little vacuum nipple on the throttle body because it was not getting very good air flow through it and low and behold next time i took it out, it was running much better. Its still not as fast as i know they can be, but i am just going take it in steps.