Return to idle very sloooow
08-06-2021, 03:42 AM
#21
Pro
08-06-2021, 11:59 AM
#22
I am having a problem with the RPMs taking for ever to drop to idle after giving it a rev to 3000/3500 RPMs. Had a buddy over Sunday with his Z06 and his RPMs don’t hang up and they drop back to idle at a decent rate. I have a 2018 automatic that is stock. I tried to download a video for you all to see, but can’t seem to get it to work. I emailed Chevy a few videos and they confirmed it’s not right. However when I took it in they say they couldn’t get it to do it.... go figure. But it still does it for me most of the time. Also when driving, I blip the throttle and it takes off, but still accelerates for a brief second even after I let off the gas... Any thoughts or ideas I can throw at Chevy? Throttle body air leak?
08-06-2021, 12:25 PM
#23
Melting Slicks
On a 100% stock car: Vacuum leaks or post MAF air induction leaks are most likely
On a tuned car, the tune itself.
On a tuned car, the tune itself.
Last edited by atljar; 08-06-2021 at 12:28 PM.
08-06-2021, 07:01 PM
#24
My guess is a vacuum leak too. get a can of carb cleaner or starting fluid and spray it around your intake manifold an some of the vacuum line connections. If there is a leak your idle will change when you spray close to it.
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Oleman (08-06-2021)
03-10-2022, 10:56 AM
#26
16 C7Z M7 with same issue, since new/stock. Only mods are BMS filter and Katech ported TB — no tune.
Has anyone figured out the root cause before I go poking about?
So far I've got:
- If boost gauge returns quickly, it's likely not S/C or boost related.
- Check for change in idle by spraying carb cleaner/starting fluid on vacuum line connections.
- Could be caused by ported TB if not tuned (had issue before installing Katech ported TB).
Has anyone figured out the root cause before I go poking about?
So far I've got:
- If boost gauge returns quickly, it's likely not S/C or boost related.
- Check for change in idle by spraying carb cleaner/starting fluid on vacuum line connections.
- Could be caused by ported TB if not tuned (had issue before installing Katech ported TB).
05-20-2024, 11:03 AM
#28
I also noticed my 2015 Z does this. It's extremely annoying. I know these cars have heavy flywheels and so don't rev like an exotic but am hopeful that a future tune will resolve this. After reading this thread, I'm going to check to see if I have a ported TB or a vacuum leak also.
05-28-2024, 01:39 PM
#29
Advanced
I also noticed my 2015 Z does this. It's extremely annoying. I know these cars have heavy flywheels and so don't rev like an exotic but am hopeful that a future tune will resolve this. After reading this thread, I'm going to check to see if I have a ported TB or a vacuum leak also.
Throttle follower is used as the throttle is opened and closed. It will adjust the responsiveness, AFAIK, as well. So a small tap of the gas may rev quicker with more down low. Too large of values in here can cause transient throttle issues, esp at low throttle.
There are no obvious vacuum leaks I have found, not sure where to start down that trail though...