vibration on highway

[pun]

i have a 86 ranger 2.9 with auto tranny,when i am going down the highway with my foot on the gas i get a vibration. but when i take my foot off or brake to slow down it goes away, it just recently started i have alredy balanced the tires. can anyone help i am lost i dont know what it can be.

 

[IMenriched]

could be alot of things...you coverd 1st thought...tire out of balance
a bad spot in the tire
bad U-joint, on the drive shaft
tie-rod end
worn motor or tranny mounts
wheel bearing
plug/wire not fireing correctly

 

[fastpakr]

Start simple. Check the Tech Library for the article on EEC-IV/OBD-1 diagnostics and run the KOEO test with a voltmeter. It may sound complicated, but there's really nothing to it. Post your results here if there are any codes. If you get a 11 pass, try the KOER test and see what that gets you.

 

[pun]

i have new u joints, trans mount, wires and plugs and tires have been balanced.

 

[clevemech]

Most likely if everything else is new then you have a cupped tire(slipped belt) or it's possible the rim is actually bent

 

[stockfornow]

if you have a carrier bearing i would check that for play

 

[pun]

where is the carrier bearing at?

 

[Gentar]

could a cupped tire cause a speed sensor error?

 

[Area 52]

New u-joints?....was the driveshaft to joint position marked before it was removed and shaft reinstalled in same position?