I've got a '97 F150 4x4 with the 4.6 and a 5 speed. When I go to take off from a stop, my engine starts to chatter or ping when I first let out on the clutch until I get rolling. It's not as bad if I use a higher RPM. It doesn't matter if it is hot or cold outside and it doesn't matter if the engine is warmed up or not. I tried taking out the little grey plug by the battery, but that didn't help. I've run a couple of bottles of Techron through it. No change. It runs good other than that. Any ideas????