i have a 1991 4 runner, yesterday i noticed that my rpm have gone down to about 500 at idle, and it's idling rougher. since i got it it has purred like a kitten until now. Fuel filter?

 

You can always turn up the idle....theres a screw on the throttle body. Wait...what engine do you have?

I know where the idle adjustment screw is on the 3vz (v6) but not the 22re (I4).

 

1991 4 runner with the 3.0

 

Yeah adjust your idle screw. Could be that with this recent temp change it needs to be bumped up, I don't know where you live but I'm in nc and we just started gettin hot weather and I had to adjust mine because of this

 

I'm in AZ. starting to have big doubts about buying this thing, it seems like there might be one problem after another.

 

Every car has problems. You should run sea foam in the tank and vac lines see if that helps. It could be something super simple or stupid like a tps sensor

 

Also it wouldn't hurt to do plugs wires filters pcv valve. Simple tune up stuff

 

PCV valve is a pain on the 3vz if your scared to take off the plenum.

But If you wanna turn up your idle a little bit, looking at the throttle body from the front of the truck, theres a screw, uh...ill put up a pic for ya. hold on a sec.

 

Start the truck. Screwing it in lowers the idle, screwing it out raises it. I believe. Youll know when you do it. You want the idle to be 850-950 when warm, so make sure the engine is warmed up.

 

How should the idle be in gear while on the brake?

 

I also forgot to add the low rpm and rough idle is intermittent. (is that how that's spelled??)

 

With an auto? No idea. Id set it at 850-950, put it in gear and see what it feels, sounds like.

On my manual I have my idle set at 1000. It keeps the oil pressure up a bit more, same with the alt. power.

 

Hmmmm...id start by checkin for cracked vacuum hoses. Just go pop the hood one day and start squeezin. Also, check the intake tube for cracks. Start with the easy stuff first.

 

Bet the intake hose is cracked. Check for air leaks! When part of my intake popped off my idle went down to 300rpm.