I’m at a complete loss.
ok so here’s the deal. I have a 94 Toyota pickup with 3.0 V6. 4x4 5 speed. 450,xxx miles on original drivetrain.

sometimes when I start it up, the idle sits right where it should.
Other times, it’s low and bouncing between 300 and 550.
Then to top it off.
there are times I’ll start it and perfect idle. Drive for as little as a block, and it’s back to low idle.
and vice-versa. Sometimes he low bouncing idle, drive a block and it isles fine.
I can find no rhyme or reason as to what causes it to do either one.

can ANYONE possibly help me out?

 

Idle speed is controlled by air flow, so..

You have one of the following.
A vacuum leak.
A worn throttle body.
A sticky linkage.
A sticky idle valve.

You can look or listen for vacuum leaks, pressurize the intake with air and use soapy water or a fogger setup.

You can inspect the throttle plate and linkage, it should always return to the same position when it snaps closed.

You can inspect the idle valve, if it's gunked up from PCV sludge it won't be happy and performance is hindered.

 

Thank you.
I’ve checked for vacuum leaks.
how do you check for a worn throttle body?
the other things I believe I’ll be able to check tonight
thanks again

 

Wiggle the linkage linkage (up/down, fore and aft) there should be zero movement of the throttle plate. A worn throttle body will have some slop in the throttle plate shaft which causes the plate to bind or air to leak in from the shaft.

 

Also check the cable itself. Mine was binding giving me "random" high idle.

 

Awesome. Thank you again