I have a 98 F-150 with the 4.2 and the five speed with 160KM. Whever I start out in first gear, give it a quick burst of gas in neutral, or just when i start it, it sounds like a diesal or similiar sound for a second. It seems kinda wierd like piston slap or something. The interesting thing is is burns no oil. I change the oil every 5000 KM and i never even have to add oil between oil changes. It is not a big issue but I was just curious if this is normal and if not what causes this. Any thoughts on this be great. Thanks

Jeff