Could my ISC cause a boost leak? ISC tested bad

[tbonitz301]

ok so my idle has been surging for a while now. well i finally got time to pull the ISC off and test the coils. 1-2(28.7) 3-4(bad) 5-6(bad). I recently did a boost leak test and found a leak at the backside of the throttle body. I thought is was a gasket, but just wanted to be sure before i put it back together. I will be replacing the ISC, but was wandering if it could cause a boost leak. Also, i think im going to save the good coil, and try a transplant next time i have an ISC go bad on me.

 

[romeen]

Yes, you can have a boost leak at the ISC motor. There is an o-ring which goes between the ISC and the TB to prevent leaks.

Also make sure it is not the shaft seals. You can check this by turning the throttle plate while the system is pressurized and listening for a change in the pitch of the air leak.

A leak past the EGR valve or one of the vacuum hoses associated with it will also cause an air leak which seems to be coming from the area you are describing.

 

[tommy260]

I noticed you replaced your plug wires, did you also replace your spark plugs? A friend of mine had an idle surge on a n/t and after she changed the plugs and wires the surge went away. I just thought I would throw it out there incase the iac replacement did not do the trick. Good luck!

 

[tbonitz301]

Actually everything is fresh. New wires and BPR7ES's. im pretty sure the isc is the culprit thanks guys