my idle problem was horrible. every time it rained my truck would not idle or accelerate. the exhaust pressure at the tailpipe was extremely high. id hit the gas and it would spit and sputter and afterfire bad. (ran great on a nice sunny day.)

things i have checked:
tps
vfam
new o2 sensor
coil
injectors
new cap and rotor
new MSD wires
new plugs (ngk)
even took off the intake and cleaned it out
blocked off EGR
backed the screw off the dashpot that was binding (caused a high idle before my rough idle)

but yesterday it rained and it didnt want to run at all. today i was poking around by the coil flicking the little black resistor grounded to the coil bracket and my idle started to jump when i flicked it. i found that it was reading an OL on my meter. the resistor was cracked and rusted.got a used one from the junk yard (for free) and it fixed the idle! I HOPE ill post again when it rains here

 

plug wires?

 

brand new

 

Nice job! Wheres the screw on the dashpot? Ive got to tap my gas pedal to get it to lower or it gets stuck at 1500-1800.

 

oops, i overlooked the wires mentioned.

 

Tubbyfatty - sounds like your throttle plate is getting stuck. I had that problem and found that the bushings were worn so I replaced it with a used unit that was in better shape. Adjusting the throttle plate stop screw might help also.

 

Ok thanks. If I took of my TB and cleaned it, do you think that would help?

Where is the throttle plate stop screw? Is it in the FSM?

 

yes it is in the fsm. im not sure where its located on the 3vz tho. you could also try using some greaseless lube in the dashpot shaft, ive herd that some times helps. mine was just screwed up from packing mud in it . i cleaned it out and still was binding so thats why i just backed the screw off form it