My friend just got an Integra RS and his idle is surging when the car gets warmed up. The idle jumps between 1000 to 2000 rpm. I've been trying to figure it out but I'm stumped. Heres the story so far:

The kid that owned the car before him decided to put in an Air to Fuel Ratio Guage. Well, first off there was an vaccum leak and that was already fixed.

The second problem is that the kid before him spliced into the fuel injector wires and soddered them back together with different pieces of wire. The wires look to be okay, but could this cause the idle to jump up and down, since the wire that was spliced isn't the same wire used in the harness?

The third thing I was sceptical about was that the kid swapped ECUs for an Automatic (the car is a 5spd). Could this be a problem?

Any imput would be great! Thanks guys!

 

try getting a valve adjustment

 

hah no way

bad IAC Valve or Fast Idler Valve are related to 75% of idle problems. Especially since you say it surges during warm up. Do a search for Idle or IACV in the tech forum, there are tons of threads about this.