when i bought the truck one of the first things i did was a tune up. Bosch +4 spark plugs, new cap and rotor, and msd wires. when i rev the engine and then let off the throttle the engine idles down to about 300 rpm and acts like it is going to stall but the returns to normal. normal idle is set at about 650-700 rpm. the only other engine mod is a stock replacement K&N airfilter