RPM Bounce/Jump Idle
Evolved Member
Joined: Feb 2012
Posts: 1,350
Likes: 1
From: San Antonio, TX
I recorded my rpm gauge on my 20 minute ride to work this morning. My idle bounced on 19 different occasions and for a total of 51 bounces. Sometimes my foot was on the clutch and sometimes it was off the clutch and I was in neutral.
Idle bounce occurs at time intervals: 1:02, 4:13, 4:37, 5:35, 5:59, 6:02, 6:43, 7:51, 11:32, 12:10, 14:43, 15:29, 15:54, 16:52, 17:39, 18:20, 19:08, 20:18, and 20:40.
wow that's pretty severe.
Mine only bounces from like 900-1K, MAX. Nothing more. And if I take my foot off the clutch, it stops. So weird. That's why I'm doubting it's tune related.
Mine only bounces from like 900-1K, MAX. Nothing more. And if I take my foot off the clutch, it stops. So weird. That's why I'm doubting it's tune related.
I checked and everything seems okay. I'm not sure what could cause this. I'm gonna log it this weekend and send it to my tuner, hopefully he can fix it free of charge. If he's gonna have to throw it on the dyno again I might as well go E85. 
Evolved Member
Joined: Feb 2012
Posts: 1,350
Likes: 1
From: San Antonio, TX
Any update? I ended up getting my car retuned from a different tuner and it seems to have corrected the issue.
Well, I sent him logs and I was getting crazy amounts of knock. I wasn't able to replicate the RPM Bounce so I couldn't log that. I did tell him about it though. So probably tomorrow I'm going to head over after work and have him log it himself and hopefully fix it. If not, I'm just gonna go ahead and convert to E85. That way he can start on a new map from scratch.
So I went to my tuner, did some logs, did some AFR smoothing. Knock could possibly be due to bad batch of gas, gonna drain tank and fill from another station and log again. As far as RPM bounce, it hasn't happened since so I'll keep you guys updated.
Evolved Member
Joined: Feb 2012
Posts: 1,350
Likes: 1
From: San Antonio, TX
Evolving Member
Joined: Oct 2013
Posts: 127
Likes: 2
From: MI
Do you have ets or ams air intake? If you do, better check if the heat shield is mounted properly .
It happened to my car onece while my friend sitting in the passenger seat, he turned off my A/C and the rpm when back to normal…
He told me it could be the fan in the hood or the windy weather effects the amount of intake air flow and causes the issue.
I checked my air intake after hearing that and found out the shield was not installed correctly …it was not able to block the entire head of intake from the engine side.
I have not reinstall the heat shield since the problem have not come back but hope the information could help you.
It happened to my car onece while my friend sitting in the passenger seat, he turned off my A/C and the rpm when back to normal…
He told me it could be the fan in the hood or the windy weather effects the amount of intake air flow and causes the issue.
I checked my air intake after hearing that and found out the shield was not installed correctly …it was not able to block the entire head of intake from the engine side.
I have not reinstall the heat shield since the problem have not come back but hope the information could help you.