1993 F150 hesistates and is being slugglish.
 

Well my friend owns a 1993 Ford F150 with a 5.0L engine in it and it's an automatic. It has a problem that when it is in gear it likes to spit and sputter and hesistate when you floor it in any gear. We went through most of the ignition we could, we replaced caps, wires and rotors cause those were obviously shot. I hooked it up to a vacuum gauge, doesn't seem like there is a vacuum leak. We punched out the cat and replaced the muffler. It seems to be fuel or ignition related and he did change the fuel filter. And it does the problem on both fuel tanks. Any ideas? We also took it to a mechanics and nothing came up on the scanner, he'll take it again and see whats wrong.

fuel filter? and did you check the plugs?

Dont know if the motor is set up the same, but my 98 f150 did the same thing. Nothing showed on the scanner, but come to find out it was one of the coil pack to the spark plug. Just my two cents!

89 Lincoln, I'm pretty sure it's the same block, and the problem was dirty injectors. They're fucking expensive for that engine, so try cleaning them thoroughly.

Reading through the post again, the first thing I'd do is a compression check.

If you have the code reader, do a cylinder balance check. I assume you know how to do it, but I'll go through the procedure anyway incase anyone else is wondering. First, do a KOER check, wait ten seconds after the last code is sent, press the accelerator 1/4 of the way down and immediately release it. Code 9 will be sent if everything is OK, any code from 1 to 8 indicates that the corresponding cylinder is not firing properly. If any code other than 9 is sent, perform the test again. If any cylinders fail that check, do it a third time.

If a cylinder fails once, you probably have a slightly dirty injector, worn rings, etc. If it fails twice, same problems but more severe. If it fails all three tests, there's either a fully clogged injector, a short in the ignition system, or completely blown out rings.


Side note: If anyone has a Ford EEC-IV or MCU code reader and needs to know how to do any engine tests, PM me and I'll get back to you with the proper procedures.

I'm pretty sure they had switched to the more reliable 289 block by then.

Yeah, 1997 was the first year for the modular 4.6.

when was the exhaust system last replaced?

might consider doing a fuel pressure test. The pump may be in the terminal stages and just can't handle the load.

What Neddy said.