Have a 93 f-150 XL 2-wheel drive truck runs awesome I love this truck bought it two months ago. Drives great but every once in a while while driving the truck will jump and spitter, last for about 10 sec then will drive just fine sometimes on my way home it will happen several times, but sometimes doesn't happen at all?? I have changed plugs, wires, distributor cap, coil, new battery. Need help driving me nuts!! When this does happen my speed tact goes nuts, up and down all over the place.. Wtf lol

 

It's almost like transmission slams in gear, feel a bang.. Weird!! Then it okay??

 

Offhand, sounds like it may be a transmission issue. Checked or changed the fluid lately?

 

Or a problem with the torque convertor.

 

The engine go in high gear and doesn't move. Then shifts hard.. Goes away then drives perfect??

 

So maybe change transmission fluid and filter? Then see what happens??

 

Forgot to
Mention the engine idle goes up and down while on park??

 

If you mean that the engine revs up without any corresponding feeling that the transmission is trying to move the vehicle, suggest this isn't good and probably not an easy nor cheap fix.

If your transmission fluid color is more toward turd brown than cherry red, it could be time for a rebuild / overhaul.

Might consider trying one of those products that chase after sticking issues - IIRC, Lucas offers an additive for this. Other than that, I would defer to other members who have a bit more experience here.

Good luck, and keep us posted.

 

Ah, forgot to mention that the idling in Park issue is likely the Idle Air Control solenoid (IAC). These tend to crud-up and hang - a little work with taking it off and spritzing some some carb cleaner usually does the trick.

 

Help