hi, truck in question is a 94 f250 460 engine. when started it runs great for about 15 minutes,then starts to miss at any rpm.when idling you can feel the miss and hear the idle start to falter. then if i shut it off for a few minutes, start up it runs fine the rest of the trip. im thinking maybe egr? im tired of replacing parts without knowing why or whether it will cure the problem. or could any of the sensors be the cause. i have not been able to code read it yet,hoping that someone may have had this problem at one time. thanks

 

I don't know much about the 460 motors but this is what I would do.

Check the plugs and wires. One of them may be going bad.

Check to see what condition the Cap and Rotor is in on the distributor.

If all those are in good shape, "most likely are by what you wrote." I would then check the electrical components. Best thing you can do is run a computer diagnostic and check for codes. That would be the best to start with. Other then that it's trial and error. Start reading up and replacing parts.


The EGR valve reduces emissions by re-routing a portion of the exhaust gas into the intake manifold
When not replaced, vehicles can experience poor engine performance, poor idle, high NOx emissions, failed emissions test, hesitation, engine surging, or CEL/MIL illumination.

The EGR valve position sensor reports present position of the EGR valve pintle to the on-board computer
When not replaced, vehicle may experience excessive or non-functioning EGR valve, failed emissions test, high box emissions, surging at highway speeds, hesitation and/or CEL illumination.

EGR vacuum solenoid works with the on-board computer to provide a calibrated vacuum source for the EGR valve
When not replaced, vehicle may experience excessive flow or non-functioning EGR valve, engine dies at idle, failed emission test, high NOx emissions, surging at highway speeds and/or hesitation.