dchavez

Hi guys,
I have a 93 F-150 5.0 4x4. The issue I'm having is that whenever I'm accelerating while in 4th gear but below 40 mph, my truck hesitates a little bit to pick up speed and I feel shuddering or misfiring. I changed the spark plugs and it helped a little bit but I would like to know what I need to do to fix this issue. Any help would be appreciated. Thank you.

desertrunner33

I doubt it's a misfire. The chance you are getting a consistent misfire only in such a specific circumstance would be rare. How far below 40 are we talking here? I mean 40 is about a normal place to shift to 4th. Maybe you're just at too low rpms. I have the exact same truck btw

dchavez

It only happens when I'm already in 4th and accelerating between 35 to 40 mph. If I accelerate harder and it down shifts, I don't feel it. Thanks for the responds by the way.

desertrunner33

Any check engine lights? I'm not super familiar with the OBD-I but I know on OBD-II you rarely get a misfire without some sort of CEL

dchavez

No lights on at all.

desertrunner33

So only 4th gear? If it happens in other gears then I would say it sounds like a fuel issue but since it's only in 4th I'm not sure.

dchavez

I had the same issue with my 05' f150 and it was an ignition coil that went bad. So I replaced it and everything was good but the 5.4 has a coil for each plug and my 5.0 doesn't.

desertrunner33

Yeah that's what I was going to recommend next. I would say check your fuel pressure and change your fuel filter. Both are pretty easy to do and if you change it and your pressure is good then you can rule out fuel and then maybe move on to electrical.

dchavez

I'm going to try that and we'll see what happens. Thanks for the advice.

desertrunner33

Yeah let me know what you find