Hi,

I am new to the forums and relatively new to owning an F150. I own a 91 F150 with 175,000 miles on it.

I have two questions.

One is a long but consistent problem. Randomly when i start my engine it makes a metal on metal grinding sound, and i can not turn off the engine. It stops when I slam the hood.

The other problem is fairly new. When traveling between 70 and 75 miles / hour the truck begins to shake very violently. It goes away as soon as im going below 70 or over 75.

Any ideas you have would help!

Thanks

 

Sounds like your starter is shot and the starter gear is sticking causing it to rub against the flywheel. Have it checked out.

Are you saying you cannot stop your engine by turning your key off? Sounds like a bad ignition switch.

The problem with the vibes at 70-75 mph is problably your tires are unbalanced. Do they have mud caked on them? If they do, something as simple as that can throw your tires out of balance.

If your tires are balanced, you could have a warped rotor.

 

The shaking could also be your ball joints.

 

Yep. A ball-joint going out at 75 mph= an accident. Have them checked out man.

 

I felt the same thing in my '99 a couple of times. After I replaced a shot universal, I never felt it again. Try checkin your joints.