JasonX

ok, so im really not that smart when it comes to vehicles. im only 18 and my parents got me a 2000 f150 for Christmas. i think its what you call a 3.4L and its a crew cab if that helps. It ran great for the first little while ( it has 200k miles on it) but after about a month or two it started this bad shaking all over. its always shaking a little but really bad when im driving below 50mph. my dad is a mechanic and he had it coded i think and it said it was missing so we fixed it. it blew several spark plugs out so we had to heli coil them. its been about a year and we have checked everything with the spark plugs and coils and have used injector cleaner stuff. i really dont want to get rid of this truck bc i love it but im so frustrated with it. can someone help me?

i should also mention that it drags down abit when climbing a hill and sometimes my check engine light will start blinking and for some reason the air condition gets slightly hotter. i usually run it with od off bc it seems to help it but not very much.

01f1fiddy

I dont think that all the problems are related but wicked shaking is normaly a broken tire belt you may not see.
Be carefull man and have it checked

JasonX

at the cost of sounding stupid. whats a tire belt?

01f1fiddy

Steel belted radials- tires are re-enforced with steel belts woven into the rubber. if one or more belts have damage it will shake badly. Look for a high spot in your tires like a bump etc. where the rubber may be trying to blow out- but a tire service garage can tell you quickly and for sure.

btw: nice gift

transmaster

With 200,000 miles The UJ's in your drive shaft could be worn out. To check this put it in neutral and roll the truck back a fourth a few time to un weight the drive shafts, leave it in neutral and chock up the wheels so the truck can't roll over you slide under it and by hand twist the drive shaft back-n-fourth. Look at each UJ when you do this. Look for missing rubber seals, rust and looseness. The originals are seal units an cannot be greased. Bad UJ can cause considerable shaking, and vibration. It is more likely this is your problem.

JasonX

i know it cant be either of those because we recently just got new tires and it still does it and also the uj's messed up awhile back so we had to replace them. we have also put new brakes on it.

HankHill

It sounds like it is one of the coil packs. They are the coils that sit on top of the spark plugs. Does it shudder just when it goes into overdrive (about 45 miles an hour)? If you try to take off very easy and watch as soon as it goes into overdrive, then slightly apply a little more gas and feel the shudder.

Goober

How's idle? Smooth?
Rev it a bit in park, does it rev smoothly?
I might agree with a bad coil, but I'd think it would be coding if missing like that.
You need to determine if the shuttering is from the engine or other drivetrain bits.
You say it goes real bad about 50, go that fast, put it in neutral and take your foot off the gas.
Does it shudder when coasting?
If yes, other drivetrain trouble.
(tires, bearings, joints)
If no, engine is missing.
(many and varied causes...)
Does it shudder under acceleration, deceleration, braking, not braking?
All parts of the puzzle.

Goober

P.s.
Just because you "just" got joints and tires, don't rule them out.

pallegrezza

I know this may sound silly and superfluous, but I've done it. Have you checked to see if the emergency brake is engaged? I've forgotten and that gave me the shakes at speeds lower than 50mph.