My 2001 Chevy Silverado 1500, 5.3 vortec, is misfiring on multiple cylinders while idling in drive. When I stop at a red light, some times, the misfiring is so bad that it noticeably shakes the whole truck like I'm in the middle of an earthquake. The hotter the engine temp, the worse it is. I bought a Diablo Sport Predator programmer/tuner/diagnostic tool to help find out what the problem is. The Predator has the capability of live data feed,a.k.a.- real time data. I plugged the Predator in and it says that everything runs good while driving, but when I come to a stop, idling in drive, like at a red light or stop sign, the Predator says my engine is misfiring on multiple cylinders, but as soon as I get rolling again, its fine. Also, when I give it gas to get rolling from a stop, it does the weird jumping/ hesitating/ stalling thing( I honestly don't know what to call it), but just for a second. The Check Engine light doesn't come on and the Predator shows NO trouble codes. I've replaced spark plugs and wires, throttle position sensor(TPS), BOTH knock sensors, cam sensor,and today I am going to put in a new fuel filter. Assuming the fuel filter isn't going to help, what is the problem? Please, someone help!!!