I had the same problem about 6 months ago. It took the dealership forever and a day to figure out what was happening. The service engine light came on also. They determined that the enigne was misfiring on cyl. 6. They replaced the ignition coil and the problem went away until two weeks ago. The engine misfired on one trip once the engine warmed up. It only did it on this one occasion and hasn't reoccured. Kind of strange.....

Anybody have an pointers on changing a fuel filter. I haven't had to yet, but I think I'm due.

 

to change the fuel filter, you have to get the special tool to disconnect the fuel line from the filter - it only costs like $6 at Parts America. Wear safety goggles if you have them, at least safety glasses. When the fuel lines comes off the filter some gas will pour out.
If you do search, you find some really good posts on changing the fuel filter.

 

Don't forget the coolant temp sensor. early FI systems relied on the CTS pretty heavily for mixture control. Sounds like the truck does fine in open loop but when it warms up and the computer kicks in is when you have your problem.

 

Thanks guys i try these things out and see what happens!

 

Something here just doesn't sound right. When I bought my '87, I was excited because it was the first year for FI in the trucks. I was disappointed, however, to find out the 5.8L engine in my truck wasn't FI. Was told Ford was rolling out the FI one engine line at a time. So, the 5.0 engine got FI for the first time that year and the bigger engines would get it the following year. The car line got FI before the trucks.

Anybody else have an '85 with FI?

Green, did you buy this truck new or used? I wonder if a previous owner dropped in an '87 or newer 5.0L engine? I think this is important to know when you go to buy parts for your engine.

 

Dennis i bought it used,but man there is no way someone put that in there! I swear it's factory,it's a mid year and everytime i go to get parts for it, i just say it's an 86! I mean everything is were it should be,nothing is butchered. The only other one that had it before me was the government,it was used on that island in maryland down on the southern shore,that has those or use to have those rare horses on it!

 

Yep, you could get a FI 302 in '85. The early FI 302 had the ignition coil mounted on the L frt. cyl. head, the air cleaner is on top of the engine(not on the fender well) & the '85 model did not have a pressure test port on the fuel rail. Fuel injection was not offer'd on the 5.8 until '88. BTW,green meanie 85, check the IDM resistor that goes from the ignition coil to the ECM, you'll see it near the ignition coil, usually taped to the wiring harness. It's brown & is about 3" long. Tap into this on both sides with a Ohm meter. It should read about 22,000 Ohms. If it's open it can cause the running problems you described. I've had several of the early FI engines with this resistor bad.

 

Tailgator,thanks man i will give it a try!!

 

MROLDV8, I have a '97 w/5.4. The way you describe your problem is exactly the way I described a problem I had to my local dealer. The radio would even cut out. It happened off and on for some time before the engine light finally came on. It was especially bad under acceleration. Finally, sitting at an idle in traffic one day, the engine light came on. Long story short, it was misfire, cylinder 7. Coil was bad. About 2 months later same thing on cylinder 6. Sounds like from the response, it could be any number of things, the service manger at the dealer said they replace several coil packs every week on the 5.4 engine. So it must be a common problem.