89 f150 302 atx 2wd
 

in park and neutral the motor idles pretty high, what could cause this? i have allready sprayed brake clean on whatever vacuum connections i could get to.

also, i suspect that my front u joint is going as whenever the truck is in drive or reverse and at a standstill, i hear a popping noise occasionally. it's isolated within the driveline and mouder up front cuz of the echoing effect with the sound traveling through the driveshaft.

also the whole truck shakes pretty bad whenever it upshifts into 3rd gear. also shakes really bad when i'm slowing down and it tries to downshift. i'm having to throw it into neutral so the tranny won't shake the truck so bad.

thanks!.