High idle help

[nepacheyenne]

My truck idles at about 1400rpm in park and neutral and aroud 500rpm in gear, i've checked for vaccum leaks and havent found any obvious ones, also smells like it's running a little rich, any suggestions? Truck is an 88 k1500, 305, 3spd auto, new plugs and wires.

 

[badazzbulldog]

tps switch

 

[sewlow]

Dirty air cleaner?

 

[gmcyukondriver]

Check your throttle position sensor. Also check your IAC (Idle Air Control) valve in the throttle body. If it's all gunked up, then clean it off.

If the 305 is anything like the 350, the IAC should have a 4 wire plug going into it, and it screws into the throttle body, so you just unplug it and unscrew it from the throttle body. However, when you're cleaning it make sure you DO NOT pull the pintle out.

 

[towman]

spray some carb cleaner around the base of the throttle body, the tbi motors are known for the base gasket to leak

 

[nepacheyenne]

Im gonna clean the iac and see if that helps if not ill check the tps, you can check it with a multimeter right? And since tb gaskets are like 5 bucks ill replace that too.

 

[nepacheyenne]

pulled the iac and its clean, no buildup of any sort on it