I've got a 93' ford f-150 5.8L 1/2 ton 4X4 engine code H. When I lightly press the gas pedal the engine idle lopes. If i press the pedal further the problem goes away or if i let off the pedal the problem goes away. This does not happen if the egr valve is disconnected. I'v replaced the egr valve, the egr vacuum solenoid, and the egr position sensor and none of them leak. What are some probable causes for this. Also the thermactor air system is inoperative during self check test.
Yeah my truck does have a throttle position sensor on it, but while I was searching for a thermactor air bypass valve at a junk yard, I saw some engines with original vacuum lines still connected. I noticed I had the vacuum lines at the egr vacuum solenoid criss crossed. I put them were their supposed to go and problem fixed.
I put the air bypass valve I got from the junk yard (of course I vacuum checked it before I took it off the engine) in and system works. I scanned the computer and I got code 111 NO DEFAULTS DETECTED!!! Yeah