So I have a completely stock 1995 integra GSR sedan(manual), and recently got my ecu changed because it began to fail. Now I’m noticing that when I’m in neutral, say at a stop light, I’m having my revs go up and down inbetween 0-1k. The mechanics told me my old ecu didn’t have this problem, so it’s most likely the new one, and it will break in.

so I have a couple of questions
1.Is this the new ecu that’s doing this
2.If it is, will it eventually go away (the rev fluctuation)
3.How long does it take for the new ecu to break in

thanks in advance guys

oh and if it matters it has 101k miles on it

 

No its not the ECU, is there any check engine lights or codes currently?
Was there any previous work done to the engine?

The fluctuation you describe sounds like a vacuum leak. or a dirty IACV (Intake Air Control Valve) located on the back of the intake manifold.
There is a thread that shows how to clean it out simply with brake cleaner and let it dry and re install.
Check around for any vacuum hoses that may have come out or loose or have a cut or hole in it. That will cause the leak.

 

ok thanks I’ll check the intakes. I’ve had bearings adjusted, as well as spark plugs replaced. Other than that none. There’s also no lights coming on in the gauge cluster so I think it’s fine.

 

Wait what ECU was it replaced with! it actually could be the ECU..