i have a 1995 f-150 p/u 5.0 the truck sometimes stalls while driving and sometimes at idle. also at a steady 40 mph it misses. it has had new plugs and wires, fuel filter, stator, and ignition control modu. it doesn't do it all the time and the dealer can't seem to find the problem, can anyone help!!!

 

pull your distributor out and check the rotor/cap assembly. It could be that the rotor has worn down to the point where it's not making good contact with the terminals.

-Flea

 

You say the engine is missing at 40 MPH. When you accelerate from 0 speed, do you notice a miss or is it while you are at a cruise mode? Do you notice a miss at idle also?
If you only notice the miss at 40, make sure you "DO NOT" allow the spark plug wires for 7 and 8 to be along side of each other from the distributor to the plugs. When running the wires from the dist, make sure #7 is placed at one end of the wire holder, then #5 & #6 then put #8 at the other end of the wire holder.
5 & 6 will be running interference for 7 & 8. The term is called "Crossfire". Its something Ford recognized and sent out a TSB (TECHNICAL SERVICE BULLETIN) to cure it.
Also make sure #2 and #4 are separated like 7 & 8, same problem. Crossfire can give a miss at speed.
If you have the problem at idle, make sure none of the plug wires are damaged which can cause a miss, make sure the EGR valve is not open at idle. I have found as the EGR Vacuum Regulator gets old, it will open the EGR valve when you start the engine without the electrical signal to turn it on.
The intake manifold gaskets can leak on both the 5.0 and 5.8. This is a common problem for these engines.
Hope this helps.
Mike C.

 

I forgot to mention the stalling part. If the EGR part is good, with the engine at operating temp, pull the Idle Air Control motor (IAC) connector. If the engine stalls, or drops below 500 rpms, you need to adjust the minimum (base) idle. Do this by leaving the IAC connector off the motor, engine running, turn the screw that acts as a throttle stop on the throttle housing.
First make sure no vacuum leaks from vacuum hoses or devices, then clean the sludge from the throttle plates and bore.
Use choke cleaner on a rag, not directly to the plate and bore area.
After that, start the engine, make sure its warm, turn the throttle stop screw until the engine reads 550-650 rpms. You will have to throttle up and release it to be sure you are in that ballpark rpm.
Shut off engine, plug in IAC connector to the motor, start up engine, and let it idle. If it acts strange, idle wise, you may have to disconnect the battery cables and hold them together for a couple minutes. That will dump all the "bad habbits" the computer has picked up. Then reconnect the cables, and drive it.
Hope this helps.
Mike C.