Will do.

 

you're in good hands with Road Race

 

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's not the intake since my A/C has been off when the RPM's bounce, that was my first guess too.

 

I adjusted upward 2 clicks of injector latency at 14 volts and seemed better (no die off yet)these couple of days,in my case.

 

Tune? Spark plugs? MAF?

 

I had the same problem stock... then I got my Greddit TBE + Cobb tune.. same issue. However, it happened probably <10 times during the past 5 years.. It only shut down once.

 

In my idle bounce situation, I know it's not my maf because I changed that out.

I haven't had my plugs checked yet but the car has 8k miles and has had this issue since about 4k miles.

If it were caused by the plugs, are there other symptoms that a bad plug would cause?

 

Not trying to be funny, and at the risk of getting flamed, are you sure this is caused by the engine or ecu tune at all? I have a 2008 GSR and got bored last night while driving home home and managed to get my car to RPM bounced on demand at idle for 1-3 secs by simply pumping the brakes hard and fast while stationary... Could it be an ancillary system not working properly causing the rpm bounce? Would this not explain the difficulty in finding the issue? My GSR is stock standard, no tune, no mods other than a CAT back exhaust system.

 

Might be an unrelated issue that causes the same problem?

I went ahead and bought EvoScan so I'm gonna log my car and send it to my tuner if anything. Will update.

But I'm gonna try that out today haha.

 

It could be a vacuum leak in your brake booster.

 

I don't think so, I checked all of the pipes this morning around the brake booster and they are all tight, the hoses are in good condition and there is no signs of any leaks or fluid loss.
I checked around the ABS control unit as well and there is no residue or fluids leakage visible.
I checked the workshop manual, and I think this might be normal behaviour. According the schematics and diagrams, there is a hydraulic unit that pressurises the brake system in accordance to the ASC-ECU. So I had a bit of a check and measure, and it appears that my brake pads are wearing at different rates (like only about 1.5 mm variance through all four), so from what I have read, I would gather that the rpm bounce I am seeing is the ASC-ECU working with the hydraulic pump (which uses the motor) to equalise the brake pressure fluid.
To test the theory I then drove the car and did the brake pump test and it did what I said previously, but on the third cycle, the car did not rpm bounce (Car was stationary through all 3 cycles), my assumption here is that the car had equalised the pressure and therefore no longer required the hydraulic pump to do anything. I then repeated the test 3 times (driving the car between each test cycle) and each time had the same result, first time rpm bounce, second time rpm bounce but less, third time nothing.
So after all that rambling, could the rpm bounce that some people experience and cannot find the issue to, be caused by something like the ASC-ECU not working properly, perhaps, the pressure sensor or a solenoid ??
Just guess work on my part, sorry but perhaps another avenue to explore?

 

Did you check the idle tables??

 

My tuner locked my tune so in my situation, I cannot check my idle tables and neither can anyone else. Kind of BS if you ask me. I paid $700 for my dual tune so it should be mine to do with as I please.

 

Still haven't logged my car. Been so lazy.