If you'r up to it, check pevious posts on the PCV hose. I started one a couple of years ago after I found that the hose goes right into the plenum directly in line with the #8 cylinder therefore dumping a lot of excess polutants and watervapour into the #8 cylinder. This can cause at the least a rough running engine and at worst a failure of the #8 piston. I recomended moving the hose to the vacuum tee in the center of the manifold (for manual trannys) or teeing into the brake booster line for trucks with an auto trans as there isn't a spare spigot on the vacuum tee if you have an auto trans. This was the first mod I did to my truck and it made a new truck out of it. I got the truck for a super deal because the dealer could't get it to run right. The next best mod is to block off the EGR. Both are dead cheap and cure a lot of driveability problems.