I just put a new Jasper engine in my 4wheel drive 92 Toyota pick-up. I now have an idling problem. When I apply the brake the idling goes up and down. I have adjusted timing and idling screw but it gets worse when I turn the idling up. I cannot find a vaccum leak either. Is there an idling sensor somewhere that could be causing the problem?

it could be your iac-idle air control cant tell you much more. you already tried timing and idle screw.

Patrick, if you get it figured out, please drop a line and say what it was because my 89 pickup with the same engine does the same thing. -Jonathan

Having the idle higher than spec will cause the problem you describe.
If you can get the idle down to spec it may solve the problem.

i have a 1991 toyota 4x4... it does the same thing how could you find the way to set it factory specs?

i have a 1991 toyota 4x4... it does the same thing how could you find the way to set it factory specs?

You can find the Factory Service Manual online, GOOGLE the FSM for a 1993 Toyota truck.

I had that problem when i bought my truck, i think i had to turn it down to about 750 http://www.ncttora.com/fsm/1993/engine.html