Crazy Idle

[Rayconstruction]

I have a 96 6.5 k2500 and it idles around 600. It seems low because the whole truck rattles. When driving it idles fine until I hit the brakes and then it drops back down around 600, and when I let off it jumps back up. Any ideas as to what could cause this?

[thefermanator]

550 is where it shoulkd idle at with the A/C off. Most likely your injectors need replaced as they are pretty common to cause rough idle once they get worn. GM reccomends anywhere from 75-125K to replace them depending on useage, but 100K is a good rule to follow. Also stick with genuinne A/C DELCO injectors as many aftermarket places use interstate mcbee nozzles that will run like crap and burn holes in pistons.