97 f150 5.8 4x4 shudder
 

Bought a hunting truck last week cheap, I new it had a shudder (e40d)--- previous owner also said the front fuel pump was going bad and that the rear pump would fill the front tank---- is this possible and if it is would that cause shudder---- would be better than pulling tranny ---- shudder is in that 45-55 mph range, haven't tried the ( tapping the brake trick to see if it stops)

My fault it's a 1995

Just sorted out a terrible shudder with my 89 5spd manual 302 4x4.
Rims were bent. Found it on the balancer. Really bad shudder hat kicked in around 45-55 mph. Reduced to a minor vibration which now looks like worn slip yoke spline on my drive shaft.
Wheel balance will cause it too.
That's been my F150 shuddering experience! Hope it helps.

Thanx bill

Adding to this, not just the tire balance, but also bad tires- broken belts maybe.


I would also look at the u-joints, that seems to be a common speed for those to start to shudder.

+1 for sure.
Bearings, ball joints can cause this as well but you get lots of other sounds and steering wheel shimmy as this is happening. Lots out there to help you diagnose that!

The tank filling issue - I've got a single tank but I've read lots about the selectors not redirecting the circulated fuel from the fuel rail back to the correct tank in dual tank setups. As fuel is continually pumped from the tanks past the regulator on the rail back to the (hopefully) originating tank one tank will eventually dump into the other one when these malfunction. (Check wiring first?) There's lots of info on this out there as well.

This is all from research, not personal experience. I'd love to have a second tank and was considering putting this all together for my truck.