1991 3000GT VR-4 is hesitating at 3000 rpm. Any ideas?

Hi all, For about a week now, at different rpms, at low throttle, my car hesitates or stutters very badly, as if I were accelerating and stomping on the brake at the same time. It happens at anywhere from 2500 rpm to 3000-3500 rpms, in first through third gears. It only happens if I hold the throttle at those rpms - if I mash the gas, it will roar through it and not stutter. The other thing, if I am idling and I steadily raise the rpms through that 3500 mark, it doesn't stutter. I also notice that it only seems to happen when the car has been running for awhile and is warm.

I have an HKS VPC and GCC hooked up, and I think I have them properly tuned, that is, I'm not running too rich or too idle, according to the readings I get on the GCC. (If anyone has the manuals to either of these, I'd REALLY appreciate getting a copy of them, and I'll pay for 'em, too. My mechanic won't touch that stuff without the manuals). The car recently was dying at idle, so I had the ICS (stepper motor) tested and found that it's bad, so I'm having it replaced. Would the ICS have anything to do with this new and very irritating problem? I also bought some fuel injector cleaner, haven't tried it yet, though. Thanks for any and all help or suggestions!

Al

1991 3000GT VR-4
Reply to
Wicked3000gto
Loading thread data ...

what is ics?

best regards rob

Reply to
Will it Work?

Hi all, For about a week now, at different rpms, at low throttle, my car hesitates or stutters very badly, as if I were accelerating and stomping on the brake at the same time. It happens at anywhere from 2500 rpm to 3000-3500 rpms, in first through third gears. It only happens if I hold the throttle at those rpms - if I mash the gas, it will roar through it and not stutter. The other thing, if I am idling and I steadily raise the rpms through that 3500 mark, it doesn't stutter. I also notice that it only seems to happen when the car has been running for awhile and is warm.

I have an HKS VPC and GCC hooked up, and I think I have them properly tuned, that is, I'm not running too rich or too idle, according to the readings I get on the GCC. (If anyone has the manuals to either of these, I'd REALLY appreciate getting a copy of them, and I'll pay for 'em, too. My mechanic won't touch that stuff without the manuals).

The car recently was dying at idle, so I had the ISC (stepper motor) tested and found that it's bad, so I'm having it replaced. Would the ISC have anything to do with this new and very irritating problem? I also bought some fuel injector cleaner, haven't tried it yet, though.

Thanks for any and all help or suggestions!

Reply to
Wicked3000gto

Sounds like a fuel mix problem. Probably too rich since you ate the ISC. I would get a logger and properly tune the mix.

Reply to
Nobody U. Know

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.