RPM drops to nearly 0 then goes back up to normal Idle

[supra2nv]

Hello everyone,

I just had my 30k mile service done yesterday. One issue, when I let off the gas the RPM dips below the normal idle range almost to 0 then goes back up to the normal idle area. The car idles fine, and doesnt do any surge when just sitting there running. Only after letting go of the gas it dips down really low then goes back up.

Could this be a computer reset issue? low coolant issue? injectors?

The dealer said to bring it back and they would check it out no problem but it is bugging me and curious if anyone here knows.

thanks!

Jack

 

[hlweyl]

I just had the same issue. Yes, check coolant level, vacuum leaks, and clean throttle body. Make sure to also spray the carb cleaner not only at rpm (around 3000) but as the rpm drops to idle. This cleans other passages in the throttle body.

The is also a procedure in the service manual to check idle. It involves unplugging the EAVC, adjusting idle, and resetting ECU. I had a heck of a time finding the idle screw on my 97', don't ask me why, it was right in front of my face.

Here's my link: http://www.nsxprime.com/forums/showthread.php?s=&threadid=34745

 

[docjohn]

Could be numerous things but I had similar problems with my 96 and it was all due to gunked up throttlebody and egr valve.I assume my oiled aftermarket air filter may accelarate this process.

 

[Larry Bastanza]

Was it doing this before the recent service? What year car??

As others have stated this is a typical symptom of a dirty throttle body.

LarryB

 

[NoggZ]

Throttle body sounds likely, as the others mentioned -- the sorry azz excuse for gas here in California has a lot to do with it!

 

[supra2nv]

took it back to the dealer today. They said this happens a lot after the coolant flush as air pockets get in there. He said this will go away eventually. He adjusted the idle and now it is almost gone.

Jack

P.S. Thanks for all your input!

 

[Peter Mills]

You got to be kidding

What does the cooling system have to do with your lost of RPM?
Mine did that last year and Larry cleaned the trottle body and very thing is fine. Cooling system...bubbles...$80.00 an hour and these guys don't know s_ _ t.