I have a 98 Ram 5.9 liter throwing a code P0505 for the Idle air control system. The truck idles very high about 1500 rpms and is sucking air thru the IAC port at the back of the throttle body. I have replaced IAC motor and this didn't fix the problem, in fact made no difference at all.

Can I get some suggestions on where to go from here?

 

Pull the Throttle Body off the intake and clean it with carb and choke cleaner. Also check all hoses coming into the intake and TB for leaking vacuum thru cracks and breaks.

If that checks out, replace the TPS and see if that helps.

 

Ok, I have cleaned the throttle body, checked for vacuum leaks, Replaced the throttle position sensor, and replaced the IAC motor. Still same problem ....whats next?

 

Did you disconnect the negative battery cable while you were doing the work?

 

I pulled the positive of the battery and left it off all night.

Will that make a difference buy pulling the neg rather that the positive?

 

Check the plug and trace the wire as best you can to look for damage. Try disconnecting the negative battery cable and turn the headlights on for a minute, turn lights off, reconnect battery. Did you remove the air cleaner housing to install the IAC and is it back on correctly with a gasket? And what brand sensor did you buy?

 

Duralast is the biggest POS there is. It might very well be defective.

 

I did remove the air cleaner but is back on with a gasket. The sensor brand was duralast. I'm going to do the neg battery and head light now. I will report back in a few.

 

Disconnect neg terminal from battery no change, I guess I'll return my duralast and get a OEM part and try that.

 

Ok, I'm still having the same problem. I have now replaced both the TPS and IAC with OEM parts and still having the same problem. Truck is still idles at about 1500 rpms and is sucking air through the throttle body. I did remove the neg battery terminal while changing parts.

What could be the problem, this is kicking my A$$