Great reference in Joe's post above. I disagree with the instructions that the dashboard tachometer isn't accurate enough. Do not attempt to make this adjustment with the engine running.
Half the battle is finding the adjusting bolt at the back of the engine. Use a flashlight to help you locate it.
I used a 10 mm. box wrench for the locknut and was able to turn the bolt by hand after loosening the nut. The way I got the box wrench to fit onto the locknut was by holding it so the offset was the "wrong" way for the nut. I'm sure you can get an appropriate tool to work.
As you can tell from studying the mechanism, higher idle is set by turning the bolt out (counterclockwise) from the mount. If your truck is idling really low, I'd start with a full turn and adjust from there.
I braced a small block of wood into my throttle linkage up by the fuel pump while I adjusted the idle. It beats fighting the spring pressure. I've found that it's best to make the entire adjustment, remove all the tools and start the engine to check, rather than try to check idle speed before you tighten the locknut. Inevitably, the bolt will turn a little while you are tightening the locknut, so plan accordingly.
It's not hard, just a nuisance.
Loren
Attention: TDR Forum Junkies 
