I have a 1993 F150 XLT.
Just last week, I noticed while driving, the engine would sputter a little,, like it was missing. It's started to get worse. Now it's like it dies for a split second. Really starting to run rough. It never fails to start,, just idles rough and jerks when I accelerate.
I had a similar problem a month ago but it was the fuel filter. That was easy to figure out,, I have dual tanks and when I switched between the tanks the problem would stop. Changed the filter on the one tank and problem solved. But that doesn't solve the problem now.
Any suggestions of where to start looking? Thanks in advance.

 

does the truck run better on one of the tanks? if so then I would suspect a fuel pump in the tank that does'nt run so well. Aslo being that you said that replacing the fuel filter helped before and now it doesn't , could mean that other parts in the system got dirty also such as the fuel injectors. Dirty fuel injectors can make a vehical stutter and idle poorly.

 

Pretty sure it's nothing to do with the gas tanks. When I switch between tanks while driving, it doesn't make any difference. When I had a problem before with the turck running rough, I would switch between the tanks and the problem would stop. It would run rough on the front tank and smooth when running on the rear tank. . I replaced the fuel filter in the front tank and no more problems. That was 5 months ago
This is something new. It could be a clogged injector. I'm running one of those bottles of injector cleaner through one of the tanks to see if it will clear up. What's the best way to clean the injectors?
I noticed that when I first start the truck in the morning, it runs like there is no problem. But after I drive it for a couple of miles or so, then it the engine starts to sputter again. It seems the longer I drive it, the worse it gets.

 

I had similar sysmptoms once and it turned out to be the ignition control module. I did all the tests and it came up fine i guess the problem was intermittent. but i replaced it anyways and has run fine since.

 

My problem isn't intermittent. It's getting worse. I took it to a mechanic here in town and he said-- ooh! could be a dead cylinder. We should first do a tune up,, then clean this or that. Next we will do a pressure test on the fuel system,, and while you are here we need to flush your radiator and brake system. Oh,, and your tires are bad too. This was a mechanic that was recommended by a friend. Of course,, all those things may be true too,, lol.
I hate going to a mechanic. I've always done my own work in the past, when I can figure out what's wrong. Just can't figure this one out.
I thought I figured it out last night. I replaced the fuel filter,, but that was too simple,, didn't fix it.
Is there another filter other than the one on the rail just under about where the driver's seat is?
It's starting to miss pretty bad now. Idles rough too.
I'm going to replace the cap and rotor today and the plugs and wires.
I thought too,, that the problem could be a clogged injector. I ran injector cleaner through 1 tank of gas and it seems to have gotten worse, not better. The guy at Napa auto parts said I should run a can of spray cleaner directly into the intake.
Maybe it just needs a tune up,, but that's too simple, I think.
I'm going to check on the price of an ignition contorl module today too.
Also,, is there a good repair manual or manual on CD,, for the 1993 Ford F150 W/5.8L engine?
I'm flying blind! Thanks for any suggestions.

 

I would start with a tune-up. Plug wires act like that when they get bad ( the do Ok cold). A bad coil will do the same thing. As for a dead clyinder....yes, caused by a bad plug wire but nothing mechanical.

Was this guy just pointing things out to you or was he trying to sell you something? I usually point things out to my customers. Not to sell them something, but to let them know what to expect in the future so that they don't get caught in a bind when something does happen.

 

Thanks stepman
I'm going to try the tune-up today. Although, I think it's a fuel problem. I bought this truck about a year ago. The first time I filled up the front tank, the gas nozzel didn't shut off and gas was running out from under the truck. When I got home I noticed that the big flex hose from the top of the tank didn't have a hose clamp where it connected to the metal part coming out of the side of the truck. I think some crud got in the front tank.
I replaced the fuel filter once because I was having a similar problem,, and that fixed it. This time I replaced it but didn't fix problem.
I'm going to trace the fuel lines today and see if there is somewhere before the fuel filter that could have got clogged.
I was looking in a Chilton Manual and it showed the electronic switching valve for the twin gas tanks but didn't show where it was. It showed 4 lines coming in and 2 going out. Since the sputter problem doesn't change when I switch tanks,, I'm thinking that something has stuck in the single exit line in the switching valve.
This whole problem started just a week or so ago. I was on empty in both of the fuel tanks. When I filled up both tanks is when the problem started. First it was a little sputter,, like the engine was missing,, but now the truck shakes pretty bad at any speed. But not like a miss in a bad cylinder,, it's like the truck--dies and starts & dies and starts. It just seems more like a fuel problem.

What's a good repair manual for the Home Mechanic?

________________
93 F150 5.8L

 

Boy is my face red!!
Thanks all for the suggestions. It's fixed.
I took Stepman's advise and started with a tune up.
When I pulled the #4 plug, it was wet. Hmmm,, probably not firing right.
Anyway-- I replaced the plugs, cap and rotor, and plug wires too.
It purrs now.
I guess when it come to my advise,, I'll stick to plumbing.
Again,, thanks all for the help. What A Relief!!!