This is somewhat complicated, akin to the old TV sets that wouldn't work at home, but worked perfectly at the repair shop. By this I mean, in the morning when it is cool and the truck (95, F-150, 4.9L, 5 spd.) hasn't warmed up yet, it tends to run great and has reasonable power. When the truck is fully warm in the heat of the day, it performs in an inconsistent manner, but never as good as when cool. What does it do? It is much more sluggish and lurches most noticeable at slow speeds in lower gears. It backfires more noticeably and it simply doesn't have as much power as when cool. It always starts quite easily and idles fine. After it has been idling and I depress the accelerator, it sputters until it clears itself and then may lurch when I release the clutch. Mileage is not very good, but I haven't done a good test because of the nature of my current driving habits. I just ran out in the front tank and will fill it and record the mileage and see how it does. It has new plugs and wires, air filter, distributor cap, MAP sensor, spray cleaned most other sensors. I'm not sure where to look next; any advice is appreciated.:

 

Have you run the KOEO tests and CM code display?

A faulty PIP sensor will usually throw a CM code. A very typical cause of your issues.

 

Hey, thanks! The truck belongs to a friend in another state, but I'll be visiting him soon and will bring my OBD II with my Ford OBD I adaptor. If the PIP is bad, I should get a code? If bad, I see some advice to replace the whole distributor because the PIP sensor replacement is difficult, problematic, ... Seems kind of drastic. What are your thoughts?

 

Typically when there is a PIP issue there will be Code 211 (Two or more successive erratic Profile Ignition Pickup (PIP) pulses occurred, resulting in a possible engine miss or stall.) in the stored codes.

If it is determined the PIP is the root cause then the replacement method is your choice. Using "rebuilt" distributors usually results in a continuation of the problem since many rebuilders never test the PIP. Sourcing a good quality name brand new distributor is getting tougher. A few have replaced only the PIP, but requires some time, patience and tools.

 

Ok. I have seen the ignition control module is a frequent problem. I hope my scan produces some kind of trouble code so I can pin this down. If it is the ICM, I assume that will throw a code. If the distributor needs replacing, I'll likely replace the ICM at the same time.

Thanks again for your input, much appreciated.

 

A 1995 F-series truck has a black colored CCD-style remote mount ICM. They rarely go bad. But...the heat sink compound has been known to dry up.

I have never seen a bad ICM trigger a code. Perhaps if the IDM signal output to the computer is bad it could, but never run across that failure mode.

If you do feel compelled to replace the ICM make sure it is a Ford/Motorcraft version and black in color. Most parts manuals are wrong, even Ford. Most places will try to sell you a gray Push-Start style ICM. They are not interchangeable. Aftermarket versions are notoriously short lived.

Here is a basic diagram of the CCD style ignition used on 1994+ trucks:

 

Recently made a discovery while dissembling a friends distributor.

I strongly recommend removing shutter wheel under rotor & checking/cleaning the pip sensor with a stiff brush & either vacuum or compressed air along with some electrical contact cleaner if really nasty.

Won't cost anything but time.

Truck in question never set a PIP code.