My question is. My 99 f250 v10 runs smooth in park, but when i put it in drive it starts out sluggish it has a studdering acceleration to it until i hit about 5 mph, then it smooths out. If i floor it the sluggisness goes away but at low rpm starting out it shakes and is sluggish. Does anyone know what my be causing this. I changed the plugs last week and it is still doing it. My battery might need to be changed because if i let it sit for a few hours in takes awhile to turn over. but i didnt think that would affect it. Any help would be great. My Truck is a 1999 f250 v10 lifted 8" with 38" stock 3.73 gears

 

Spark is king...should have put $$ into the battery first..it is the source of many problems as they age...your notes about the battery make it simple..get a new battery asap.

 

Thanks wryfox. I took the battery out of my 1997 f150 and slapped it into my truck and it solved the problem. Sometimes the easy fixs are the ones that drive you nuts the worse.