The truck is a 94 22re 5spd 4x4, the first problem is the truck idle jumps rapidly between 1000 and 1200 rpm, if i press the brake it will hold at 1500rpm. On warmer days it idles normal most of the time but since its gotten colder it has gotten a lot worse. Its throwing a code 26, i'm thinking its either the tps sensor or vacuum leak. The next problem happens at 2500rpm and theres a light tapping noise coming from the transmission. I just bought the truck a few months ago and it looks like the transmission has been replaced with a used one.

thanks for all of the help

 

The first problem sounds like fuel pressure regulator. Is this an automatic or 5spd?

 

It has a 5spd transmission.

 

First off, check and adjust your TPS. Here the info for that project

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

Once that is in order, lower your idle anywhere between 750-900 RPMS (whatever range it runs smoothest at). Increasing the idle above 950 RPM's causes the computer to go in "fuel deceleration cut" mode and that's when you get the varying idle.

Check and adjust your timing. It should be 5 degrees before top dead center WITH the TE1 connector shorted.