I have a 99 4.6 manual tranny and I was driving and I went to pass some one and it starts to shake and bog down but not when u are at normal rpms no cel so I start to unplug each injector one at a time and see which one don't have any effect and I find one and put a new plug and wire in it and every thing is fine but still the same when driving ......any thoughts

 

Make sure your tires are tightened my dad almost lost a tire cause his truck was shaking. The lug nuts were a little loose

 

I don't think its that it don't it when I release the gas but ill check

 

Coil?

 

Idk but its not doing it while sitting could a really realy dirty fuel filter do it

 

I know what you mean, I think it could be the drive shaft loose one of the weight or it is out of balance, it does it only when you let go the gas or when try to stop? or does it all the time?

 

or could be the u joint, check them up and make sure they are ok.

 

Only when I push the gas down hard like passing some one it like falls on its face its more of a rocking and sputtering

 

I had some real bad shaking lately too and only started at faster speeds, slowly got worse and worse and soon couldn't go 40km without it shaking, couple days later it stopped when my dad was driving - all the bolts on the front drive shaft had backed off tightened em up and she's been all good since

 

if it shakes when ur giving it gas it could be several things like the EGR VALVE or a bad ignition coil or spark plugs