Ive been having this bouncy idle issue, it revs from 850 up to 2900 rpms just up and down and ive done a number of vacuum leak test, cleaned the sensors with sensor cleaner, checked for air in the cooling system, i got a new idle air control valve straight from honda, i also re-adjusted the outer housing inside the fast idle valve, checked for any air leaks in the intake manifold. i have done everything that needs to be done to fix idle problems on hondas/acuras and nothing has worked for me, i have good compression in the combustion chamber i dont have a "check engine" ive had people specialized on hondas look at it and they cant solve the problem. Is there a chance that my ECU has gone bad? thats the only thing i haven't checked, please help me because its driving me nuts

 

TPS?

 

Air in the cooling system, check vacumm hoses or Fast Idle Valve aka FIV located just behind the IM plenum. I bet that's your problem.

 

You can do a test on the FIV by simply cutting out a piece of cardboard from a cereal box, shape it to the size of the FIV sensor ports, block the ports from the sensor to the IM by simply putting the cardboard in between to block it off. If the idle issue stops thats your problem. Mine had a idle issue too I simply deleted that sensor. Ive been running a block off plate on that sensor forever now without any issues and no check engine lights.

 

Unplug the iacv when the engine is completely warmed up. The idle should drop to 500 - 600. If not, then you got a leak somewhere.

When the car is completely warmed up open up the fitv and you can make sure it's tightened down clockwise.