which vacuum lines off a 96 civic ex can affect the idle to go higher? i changed the FPR and the PCV lines already which other ones do i need to check? maybe the cruise control or EVAP you think? any help is appreciated.

thanks
james

 

Any line that connects to the intake manifold can have an effect on your idle if there's a leak. I would look at the IM and just start checking lines.

 

so your idle is too high? or too low? if it is too high a common problem ive seen is the IACV (idle control valve) gets dirty with carbon build up and tends to make it idle higher, same with the fast idle thermo valve, most of the time it seemed to be the fast idle thermo valve, if you dont know where that is located on your throttle body open the hood, look on the throttle body on the side where the opening is, it will be held on with two phillips screws, see if you can take it off and clean it with some throttle body cleaner, also inspect all your vacuum lines from the TB like inspyral said...... but my guess would be its a dirty fast idle thermo valve or IACV, the IACV is on the front of the throttle body and has a little sensor connected to it... let me know if that helped....

 

on my throttle body there is only the map sensor, the iac and the tps.

 

What's the best method to check for a leak in a vaccum line?

For old bicycle tires we used to just blow up the tire and put it in a deep tray of water or put liquid soap on it to find the leak... I don't think that's a good idea for the vaccum line though.?.

 

You can spray carb or intake cleaner on your vac lines while the engine is running. If you spray a spot, and the idle goes up, there's probably a leak there.