Have a 96 F150 with the 5.0, it has started ( occasionally ) to shake very badly sometimes on start up. It will run but shakes terrible. Then when you put it in gear, it dies. After it sits a while, it usually starts and runs normally. I have replaced the distributor cap, rotor button, plugs and wires thinking that would fix it but no such luck. Anyone got any ideas? I should also point out that it has 256K miles so its probably just plain worn out but it is and has been an excellent truck all these years that I have owned it.

 

maybe it,s fuel ! maybe the fuel filter is starting to clog up !

 

Ok, I agree; this could be the begging of a fuel problem. Best bet is to attach a gauge and watch what happens when you turn the key on before cranking; it should go up to about 45 PSI and stay, not bleed off.
When started, the pressure should be around 30-45 psi, and steady. Let us know!

 

my 96 is the same way and it test the same as yours ! my nephew checked the regulator and it was good and he said there is a filter on the pump and it could be almost clogged up ! like i said, change the fuel filter first ! i changed mine but even though it needed changed it did not improve it any ! if you have duel tanks switch to the other tank and see if it,s the same way ! let me know what the problem was if you find it !

 

Yah I plan to change the fuel filter this weekend. Its past due even if it isnt the problem. Will def check the pressure and let you guys know what the results are.

 

if you can try to run a comp. test it will tell you if you might have a much bigger problem.

 

Well I didnt get a chance to check the fuel pressure or the compression but i did talk to a mechanic I work with who said it sounded like it might have water in the fuel. I poured in some stuff my father in law had and it has ran fine for over a week now. I think the problem is that when I drove the truck, I filled it up when I needed gas. Now that my son drives it, he probably only puts a few gallons in at a time which apparently allows condensation to form inside the tank. Anyway, I am going to keep driving it and see if it happens again. Thanks to all for the help and suggestions.