I have a 1985 Chev K1500 truck that idles slow. I have put a TBI gasket, new regulator, check fuel pressure it is 10 pounds, new map sensor, new O2 sensor, new ecm, checked timing, checked compression, normal vac. Done all of the things the service manual suggested. This problem happened all at once. Any ideals
Clean out the idle air control valve and see what happens
July, 11, 2011 AT 11:21 PM
Check for an EGR valve not closing all the way at idle first.
You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.