Ok I've searched recent and archived post for this exact problem but never found any... or maybe i'm just blind...

I Have a EG Coupe EX that has a DX Motor...
It throws check engine codes:

19...Automatic Transmission Control Valve (It used to be auto converted to 5 speed)
21...VTEC Spool Solenoid Valve (DX Motor)
41...Primary oxygen sensor heater (I'm guessing something to do with the o2)

OK to the problem... the car idle surges between 800-1300... And the idle surge is fast not slow...like every second it revs up and drops... revs up and drops... I want to stop this idle!!! PLEASE HELP!!!

 

awww comon sum 1 has to know about this... ITS HONDA-TECH!!!

 

i have no idea why it would be throwing a vtec code with no vtec?? what ecu are you running?

anyways umm i would say the IACV (idle air control valve) it is what usually causes the idle to bounce like you are saying.... mine is doing the same thing.. maybe not as rapidly but it bounces....

 

hahahah u are obviously still using the p28 automaitc ecu from the ex right??? hence the cel for the automatic shift solinoid and the vtec solinoid. im surprised you dont have one for the vtec oil pressure.

okay anyway check your idle air controll valve or first you can go to auto zone buy a can of throttle body cleaner unhook the intake tube from the car off. turn the throttle to where its wide open and spray the can in the intake manifold all over in there and in all the creveces in the throttle body that should help and if not you may need either the idle air controll or pcv good luck

 

i dunno about spraying that **** all in there because when all that junk and dirt breaks free where is it supposed to go? into your injectors then ports and head and all that ****. i just got done swapping an intake mani and i had this problem i sprayed all that **** loose and then where did it go?? into my engine.

not a good idea, if you really want to get it all cleaned out. get it dipped in acid or something..youll have to remove all the sensors though.

i would check your IACV first off then definetly check like siregcivic said, maybe your using the auto ecu when you need to be running the 5 speed.

good luck with whatever you choose to do