I have a 1986 F150 4x4, and I am having some issues with it sputtering and cutting out while driving. I recently started driving it again after it sat for over a year. When I first started driving it again, it would sputter a bit going up hills in third gear. It drove fine in all the other gears, just messed up a bit in third. So I figured no big deal just some old gas, or just needed to be ran. I have been driving it for about a 2 months and up to about a week ago it was running okay. Then it started gradually getting worse until it started doing it in every gear after It reached about 2000 rpm. I talked to some guys at work and they said to replace the distributor... I did that and nothing changed. We talked about it a little bit more, and decided to try replacing the fuel filter. So yesterday I replaced the fuel filter, and it ran perfect and didn't miss a beat. I gave it steady throttle, and it kept climbing. Never sputtered. I thought the problem was fixed, but this morning I drove it to work, and it is doing the same sputtering as before I changed the filter. I've looked up what can cause misfires, there is quite a bit that could be wrong. Can anybody tell me what might be causing this? Is there possibly trash in the fuel tank? Bad gas? Any advice would be appreciated.

 

What engine? 302 fuel injection?

 

302 5.0 liter V8 EFI

 

Pull the codes. Here's how to do it, all you need is a testlight or old voltmeter with a needle.

EEC IV Self Test hookup

 

44-AIR system inoperative
34-EVP-(R) EGR did not respond properly during test EVR-(O,R,M) EVP sensor is/was high PFE - (O,R,M) PFE sensor signal is/was out of range
77-System did not receive "goose" test - see TESTS

 

https://www.ford-trucks.com/forums/1...4-5-0-efi.html


Did you check the filter (don't know how many there are on your application) they identify on Post #193 of this thread??

 

I'm not sure of my truck has that fuel filter. I just know of the one I just replaced. Would a bad egr valve cause that much trouble?

 

Man I had the same problem with my truck in the past it ended up being a bad fuel pump. I would look into that.

 

Yes also a stuffed catty inverter does the same thing.

 

Doesn't look like any of those codes are serious enough to cause the problem. You did need to check though. Does it have dual fuel tanks? I have heard the switching valve can have a fuel filter in it also.

 

Here's the regular fuel filter.


Here's the other one that may be located in the switching valve or on the frame in it's own housing.

 

Yeah, I already forgot about that! Another guy over the past several weeks had similar problems, most of which turned out to be that filter which I think is located on top of the gas tank(s) or someplace thereabout. Apparently, this is in 1985.5 - 1986 models only, read here for more info:

https://www.ford-trucks.com/forums/1...4-5-0-efi.html

 

It's just a single tank. So it only has 1 filter. I replaced that two days ago. So bad fuel pump??? What else could it be?

 

Courtesy of 85lebaront2


I hate to be repetitive, but can you absolutely confirm you do not have this filter anywhere on your truck?? Reason being is 15 pages on a single thread, multiple codes and numerous hours were spent trying to work through a problem exactly like you describe, all due to a single filter

 

This can also cause the issue