Gavin60

Hi Folks,
Long time ranger owner here and I had to move up to a F150 for a lot better towing.
I have a 2000 XLT crew cab F-150 which shakes at around 45-47 mph and stops shaking at around 53 mph.
I can feel it coming from the front end and up through the steering wheel.
The tires are in decent shape...nothing cupped or flat spots etc.

I can be on level ground when it starts the "shakes" with a slight throttle to it. However, the shakes will completely disappear if I romp down on the accelerator pedal in the same rang of 45-53 mph.
It will also appear if Im in the same mph range while climbing a slight hill, but it will oddly disappear in the same speed range while going down hill coasting and not using the accelerator pedal. (The shakes disappear as Im coasting but gaining speed down hill through the range of 45-53)

It does feel like is has a slight "cam" to it as it idles but does not seem to be skipping or cutting back through acceleration.
Im not sure if this "slight cam" Im feeling is normal to an f-150 since I have never had one before.
It is a trition 5.4 with about 200k on it.
No check engine lights are on.
I have gone underneath it looking for bad u-joints and loose steering/ front end linkage but could not find anything loose or worn.
Any help narrowing this down would be a great help.
Thanks!
Gavin

texansport

I hauled a trailer that did essentially the same thing. Take it to a tire shop and get your wheels balanced. It was a super quick/cheap/easy fix. A piece of lead may have just come off!

If I'm wrong it won't cost you hardly anything.

Best of luck!

Gavin60

Hi Texan,
A friend said the exact same thing.
Today the "service engine" light came on and I had one of those folks at Auto Zone put the OBII, on it and it said bank 2 combustion too lean and cylinder 7 & 8 misfire detected.
I guess I need to replace some plugs and coil packs???

texansport

Or fuel injectors. I would still check the tire balance just because it's easy and cheap. The engine light could just be a coincidence since it hasn't been on/you've already had the problem.

Another note, if the guy put a can of slime/fix-a-flat in the tire but didn't drive it a long enough distance after filling it, it'll settle on one side the tire and throw it out of balance.

texansport

I don't know about your year, but the 04-08 150s require you to take off the air intake to get to the spark plugs, which makes an easy job a pita

Gavin60

Hi Texan,
Its a 2000 xlt super cab with the 5.4
Fuel injectors on both 7 & 8 too?

texansport

Honestly couldn't tell you :/

Gavin60

I replaced the coil pack on 7 & 8 ( OBII) said it was misfires on each one, but #8 had the correct ohm reading...maybe a rubber boot problem. But #7 was probably the culprit it had a lot of crud around the boot which probably gave it a short. And the Ohm reading was way off.
It purrs like a kitten now