Hi all, I am at wits end and coul use some advice. My symptoms started about a month ago while driving into town. It felt like a clogged fuel filter so I changed it.( first time I changed it bought the truck 8,000 miles ago). The truck had cooled off and I thought that was it. What happens is that after you reach 180-190 degrees and put it under a load ie: go up a hill or get hit with a head wind it will start running very rough. The condition will get worse to where it will not keep speed even at 15 mph until you let it cool off a few minutes. First thing we did was to ensure uvch were tight. The ses light would light intermittently(and has since we bought the truck)but especially under acceleration. Also consistently would get p1316 and occasional icp lower than desired.

I started all diagnosis I could without autoenginuity which I have since bought. The icp sensor did have a little oil in the connector and a motorcraft replacement did make it run smoother but did not solve the problem. Broke down and bought an AE from riffraff. A buzz test revealed that usually #3 would get hi/lo and sounded very weak. Swapped solenoids and weak sound stayed with 3. A cct would usually show ok but would show 3 and 8 faults when hot. Read on here and elsewhere and replaced the CPS with a new motorcraft from a 96 or so. The CPS that seems to have best reliability. Had a definite difference in idle but our problem remains.

After much reading we decided to replace one injector #3. 4 and 8 are marked remanned. Replaced injector and really thought we had fixed it. Flogged on it as hard as was feasible to get air out of the lines. Loaded up the family and the problem resurfaced. However, I could not make the problem get as bad. The truck could maintain 50 mph and just a minute or two of off time would restore full function for several miles. Easy driving would not exhibit the symptoms, though we only went about 20 miles back.

 

I have decided to check the clearance on the armatures.
1-.0015to.002
2-.002
3-.0035-remanned injector form dieselpowerproducts
4-.004-has reman plate over solenoid
5-.002
6-.0025
7-.0015to.002
8-.004-has reman plate over solenoid

When the problem starts the icp will begin to fall and ipr will rise up to 64%. Cold icp is around 750 and falls with temp to 5 something when warm. Before the problem starts icp will hit 2890 or so and the truck feels very strong. Once the problem starts it will not go away until the truck cools off a moment idling or easy driving while the problem is happening the icp and ipr look to have normal readings. Hot restart immediately after shutdown while the problem remains is as fast as cold start so I don't think the ipr is to blame but welcome y'all's opinions

Thank you for reading and for any advice

P.S. Truck odometer shows 119,000 and although I have no idea the authenticity of that, the suspension and what not seem to corroborate this. The truck appears to have spent most of its time as a farm truc. Lots of dust under instrument cluster, wear in the bed, scratches to paint etc...