Chuki

Without the a/c on my 3.0 runs great, nice and smooth... I turn the a/c on it idles up and everything just fine but it gets really rough. It will idle up to about 1100-1200RPM but it seems almost like a single cylinder was disconnected almost.

This past month I've been using the a/c alot and my gas mileage is really crapp this last tankful I was lucky to pull 14mpg, which its usually around 17mpg.

Any ideas?

CILO

Have you ever checked/adjusted your tps? it may seem unrelated but its possible that its off by a hair and while under normal load you dont notice anything, the additional load is causing defects to become more noticable. Also, I think there's a switch that kicks up the idle when the a/c is turned on. perhaps the switch is malfunctioning?

Chuki

I'm not a 100% sure, but I do think my TPS is crap, I haven't been able to get a solid answer.

If I hook up my ohmeter to the VSA and slowly open the throttle the resistance increase for about the 1st 1/8th inch, then drops then increases all the way to full throttle. Nobody can answer my question if this is normal or not.

CILO

sounds like you have a burnt spot in there. I recall someone mentioning what you did and if what you mentioned happened, it was fried in one spot. However, i think they also said that you shouldnt use a digital multimeter, the needle ones are better suited for the task

did you try testing the tps the way its outlined here:
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
and here:
http://personal.utulsa.edu/~nathan-b...93throttle.pdf

if not, it wouldnt be a bad idea. I had idle problems and power problems with my 4runner and after adjusting the tps the difference was night and day.

^VooDoo^

Also check the AC idle up valve ( big plastic screw on the passengerside fender where all the vacuum hoses connect) Make sure the hoses dont have holes or cracks in them.

MMA_Alex

not to hijack, but im trying to adjust the tps, and i cant manage to get the screws to loosen. anyone have any advice? i removed the t-stat housing to get access to the screws.

TNRabbit

Run the engine in the dark and look for any spark jump from a wire. Your problem sounds EXACTLY like one that was on here a while back and that's what it was...

Chuki

By using the needle type (analog) style multimeter is how I found the resistance drop. My digital one didn't show it as clearly... Damn anyone know where I can get a TPS on the cheap. Dealer wants $80 and I don't have any kind of money to be throwing at this other then exactly what it needs!

deathrunner

Try:

www.rockauto.com
www.car-parts.com