i am usually pretty good at these issues, but for some reason i am having a hard go at it.

2004 f250 6.0l 6 spd fx4. 139k miles. full bullit proof done 15k miles ago.

been running and driving just fine, then due for a 5k miles oil change, drove in fine, and since then almost everytime its cold, it bucks and jerks in low rpm load from say 1100-1800 until it warms up.

i thought the oil filter was a possible issue, so i replaced with a second motorcraft filter. used rotella 15-40 oil and have been using the hotshots secret additive for a year. (runs better every oil change) i also have a bully dog cold air kit on the truck, and i blew across the top of the filter to make sure it was clean (it was).

i thought i may have had a peice of lint get through and land on the maf sensor, but i removed it and cleaned it a couple times with no change. i also checked the map sensor hose and nipple for restriction or debris, but also clean.

i had a ds708 scan tool for a short time and ran codes, none. no engine light either. ran the scanner in active on the oil temp sensor and the coolant sensor, the both started at the same temp and consistantly rose up together to temp. power balance looked pretty good, just a little drop in #4 just like it did before this issue.

when driving it cold, it bucks and jerks while it is climbing to operating temp. if looking at the guage, it it roughly about 2/3 of the way to the normal operating temp when it will run fine from there on. if i let it get below that 2/3 temp from sitting, it will do it until it reaches that point, and run fine again from there out.

anyone have some ideas??? i dont have the same scanner now, i am trying to get another one, any help at this point would be greatly appreciated.
thanks
tim

 

What's the FICM and engine voltage?

 

when i checked the truck and ficm voltage on the scan tool it was good. if i recall correctly it was 12.2v static, 13.49v running, and the ficm was 47.48v

if i get another scan tool soon like i hope, i will recheck just to verify, but i know when i checked it last it was ok.

 

i am starting to think it is possible that when i did the oil change, i used a different oil, i was using napa brand 15-40, but there was a sale on the rotella. it sure seems like when the coolant or possibly the oil get to a certain temp, everything works like normal.