High RPM with no pedal input

[MROCGUY]

i am getting this condition of 1500-2000 rpm going through a parking lot, usually after starting the car and rolling out and that's foot off of the gas. typically 10-20 mph. if i brake to slow down, the rpm's drop.

to the best of my recollection, this only started after getting tuned. it may be happening more often with the ethanol tunes versus the 91 tune, but i'm not sure. i will switch to 91 when i burn this tank of ethanol.

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[iamcvr]

Do you wait for the car to get up to operating temps, or do you key-on and go? The tuner may have set your cold start/warmup RPMs higher than stock, but iirc those RPM windows are overridden once you begin to drive it.

 

[MROCGUY]

Happens after I have driven. Just pulling in a driveway and they go high.

Cold start rpm's are consistently at 1250

 

[iamcvr]

What does your vacuum look like during the problem vs. when it doesn't do it? If you flash back to your stock tune does it still do it?

 

[MROCGUY]

What does your vacuum look like during the problem vs. when it doesn't do it? If you flash back to your stock tune does it still do it?

I have to burn through the ethanol first...that could be a couple of weekends from now

As for vacuum, the only way I have to check is the onboard gauge and I have no idea what to look for or how to read it

 

[iamcvr]

Onboard gauge is generally fine for simple troubleshooting. It's not perfect but it's a good "marker". I believe for stock cars it should be 20-21. Start with the simple things before doing stuff like taking a multimeter to the throttle body, swapping spark plugs or O2 sensors.

Also try to do the idle relearn process - unplug battery, let sit for 5-30 min, plug it back in, turn off all accessories, turn car to ignition, wait for it to fully power up, start the car, turn on the AC, drive around town making sure to MANUALLY go through ALL gears and spend at least a few seconds in each one, then park up and shut the car off for a few minutes and turn it back on. Sometimes that just works, like restarting a PC, lol.

 

[MROCGUY]

Onboard gauge is generally fine for simple troubleshooting. It's not perfect but it's a good "marker". I believe for stock cars it should be 20-21. Start with the simple things before doing stuff like taking a multimeter to the throttle body, swapping spark plugs or O2 sensors.

Also try to do the idle relearn process - unplug battery, let sit for 5-30 min, plug it back in, turn off all accessories, turn car to ignition, wait for it to fully power up, start the car, turn on the AC, drive around town making sure to MANUALLY go through ALL gears and spend at least a few seconds in each one, then park up and shut the car off for a few minutes and turn it back on. Sometimes that just works, like restarting a PC, lol.

I have Forscan and an SCT BDX programmer..if that helps anything

 

[iamcvr]

Oh definitely log it with forscan then next time you both have the issue and don't. Just to see if there's a difference. I can't imagine an intermittent vacuum leak but these cars have some weird gremlins.

 

[MROCGUY]

Just got off of work. Vacuum is at 19.xx.

Idle is 750, as set by the tuner

 

[Pistol_91]

If it doesn't do it with the 91 tune then it's the E tune. Something is off. If not sounds like a vacuum leak. What are your mods?

 

[MROCGUY]

If it doesn't do it with the 91 tune then it's the E tune. Something is off. If not sounds like a vacuum leak. What are your mods?

just the exhaust and tune

 

[Pistol_91]

just the exhaust and tune

Yeah that's strange then. Try going back to 91

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