Two days ago i traded my 90 ext cab for a 90 4runner. The runner has the 22re and for some reason when im in gear and driving then i shift into neutral the rpms will stay at 2000 or so until i hit the gas a little bit then it'll go down to normal idle. It doesnt do this all the time but it happens a lot. Also sometimes when i press the brake my rpms will go up then down up then down. I heard it had to do something with The MAF? is this right? And how can I fix it?

 

Check to see if the flapper is moving freely and not sticking is how you can check it. I don't think it is the AFM but from my experience it is the dashpot that is holding the throttle open and is why when hit the pedal quick it will push the plunger back down to where it belongs.

The part I am talking about is where the throttle cable or rod attaches to the throttle body. I have seen that plunger sometimes just needs a cleaning or lubricating.