Hey, I have a 91 SR5 auto, when I come to a stop the whole thing shakes, somtimes it doesnt do it, it never does when the a/c is cranked. I noticed the battery gauge needle jumps around when it does shake. The battery that is in ther is under sized for the truck. I have been meaning to get a dry cell. Would changing the battery help or is it somthing totally differnt?
I love my runner, I beat on it a little but I want to take care of it. Is there anything I could do?

 

try adjusting your idle, it should be near the intake manifold

 

What's the idle speed when it shakes?

I would go ahead and replace the battery too.

 

It idles at just above 500 rpms, Thanks for the help.

 

Time to clean the throttle body and get that idle back up around 7-800. The idle speed should be on a sticker under the hood, not sure where on your year.

My guess is the reason it doesn't happen when the AC is on, is that the automatic idle speed compensator kicks in and brings the idle up.

Good luck!