so i have the check engine light and i have a scanner i check the scanner and it says i have a idle control system malfunction. so i took off the idle air control valve, thinking it was dirty and is maybe getting stuck. so i cleaned it as best i could. and put it back on.

now the car is idling and 1500rpm consistently, but when you tap the throttle it will drop down to 1000rpm then sometimes stop and hold at 1250 and sometimes go back up to 1500. then also sometimes (only sometimes) it acts like i have a vacuum leak some where. then it goes away. and finally itll stay at 1000rpm then throw the code. also it throws 2 codes for the idle control system malfunction. so what do i do?

car: 98 civic DX

 

You try swapping it for another? When its running if you remove it do you hear any change in the rpms? If not you need a new one

 

i swapped it already. and no change. when the car is running, if i disconnect it. it immediately throws a code(of course) and starts idling at 1500 but the rpm i guess bumps every second. there is a dramatic change the car runs a lot shittier lol.

 

Do you have a multimeter? Test the voltage on the connecter.

 

i got a new one from Honda. and i threw it in. i started it up it ran perfect then it threw a code again. im reseting the ecu as we speak so hopefully that should fix it

 

i used to have that code on my 99 ex, it was the iacv, got it replaced, then it was fine

 

get some carb cleaner and spray it around the manilfold and hear for any engine change. if you do then you heave a vacumm leak.

 

i did that carb cleaner stuff when i ran that code and it didnt work...and trust me, i cleaned it a lot....about every week, i cleaned my filter, cleaned the throttle body + manifold with that carb cleaner, and waxed my car

 

Just a possibillity but most of the time with IAC you need to unhook the battery cause imagine your old IAC was at 25 steps and you put the new one on and it is at 0 steps the computers memory still thinks it is at 25 steps and adjust from there which is wrong and clearing out the light with a scan tool will not do this cause all though you lose all your ram your learned rom is still stored in computers memory and needs to be erased please allow 10-15 min to discharge the system.

 

did that.still throws a code

 

it could be the bolt that is on your throttle body that controls the idle. try to adjust that? or maby there is something wrong with yoru tb?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sharik &raquo;</TD></TR><TR><TD CLASS="quote">it could be the bolt that is on your throttle body that controls the idle. try to adjust that? or maby there is something wrong with yoru tb?</TD></TR></TABLE>yea it cant adjust the idle. so im thinkng that it must be gettin air in behind the tb somewhere.

 

bump

 

the iacv isnt closing so what does that mean?