Don't know what it is you're working with here... Anyway, probably start off by cleaning the MAF sensor. Are you using an aftermarket oiled air filter (K&N, etc)?

 

and while your cleaning it, look at all your vacuum hoses. If your fingers turn black when you grab a vacuum hose replace it. Vacuum starts in the engine and the first hose off the engine is typically on the backside of the intake manifold. Look for the hose next to the distriburator cap, it will then go into a tee fitting. One hose will go down to the t-case, one hose will go to the HVAC controls, and along this hose it should split off and go to a black ball. Depending on the year of your truck the HVAC hose enters the cab of the truck through the firewall, where is determined by year of truck. Older trucks it was in the center of firewall behind engine, newer trucks next to drivers side fender and its a real bear to get at, so dont go tearing it up.

To clean the MAP sensor spray ti with brake cleaner. Do NOT touch the sensor wire in the middle, if you break it you just bought a new MAP sensor.