ok my buddies 96 civic lx, the idle on it sucks big time, itll rev right up on start up, but afterwerd itll screw around reving between 1,000 and 2,000 rpms up and down, and up and down. we replaced the old throtlle body with a used throttle body and yet it continues to do so. so i doubt highly its the tps. unlikely yet possible, yet more so possible its the ecu. heres the deal the idla air control valve is supposed to be recieving betwween 16 and 28 volts, yet all it is getting is 12.5 volts, is this the only possibility...the ecu that is.......answers will help

 

Could be a bad ground somewhere.

 

HEy I have a 96 Honda civic lx and its doing the same thing its not a ground i highly doubt its was the throttle body to be honest I have no idea and I don't know what to do can anyone help us out? Ay Andy LOL (Insides Joke)

 

yeah, check all the grounds, the ignition timing, and then the vacuum hoses. i guess if you have access to another ecu, plug it in and see.

for the vacuum hoses, spray a little carb cleaner on the fittings while its running, and if its leaking, it will bog down a little. but my bets still on the timing.