Where to Start?

[Fireman5606]

Ok I know this seems to be a popular topic lately, but I need to know where to start. I have a 2003 F-350 with 96,000 miles (apparently the magic #) and for almost 2 weeks now it has been running rough until it reaches about 160* ECT. Once it gets warmed up it runs like a champ. The fuel mileage hasn't changed, and power is normal once it is warmed up. I have read everything from needing to get the ECU reflashed, to I need to replace the FICM. My extended warranty died about 3 months ago, and I am past the 5 year cut off so everything is coming out of pocket and I really don't want to start throwing $800 parts at it without somewhere to start. There are no codes new or old, no CEL on, new motorcraft fuel filters, new motorcraft oil filter and oil, and I have gotten fuel at the same place since the truck was new. I haven't spent much time working on 6.0's since I have had almost no trouble out of mine since new, but I know gas engines will throw a code most of the time with a misfire on a cylinder and that is what has me stumped. The truck computer is not giving me anywhere to start, so I am looking for experience with this problem. What is the likely culprit and where should I start spending my lifes savings? I have been reading other posts for over 3 hours now and haven't found an answer, (Forgive me if I overlooked it). Thanks in advance.

[Borderwerx]

when did you change your oil? I'm kind of in the same boat and I just changed my oil with 15x40 and right after that it started really hard and ran like crap till it warmed up. Temps have dropped to the mid 40's and I was told to change the oil to 5x40 and it should take care of the starting problems.

[Fireman5606]

I changed the oil about a month ago. I won't tell you not to try 5-40, but I have ran 15-40 year round since mine was new and have had no problems until now. The temps here hardly ever get below 15-20* though. Mine starts fine just runs like crap til it gets warmed up. I dunno where to strat and I dont have several grand lying around to throw parts til I get it figured out.

[dxusmc]

getting the latest flash from ford would definitely be the best place to start if you haven't done it already. should be under $100 to do this and doesn't take long

[Fireman5606]

Originally Posted by dxusmc

getting the latest flash from ford would definitely be the best place to start if you haven't done it already. should be under $100 to do this and doesn't take long

Well I don't have the latest flash I don't think, but I have never had this problem in the 5 winters before now so why would the flash make any difference? Unless the computer can forget how to run in cold weather? I don't know......could be I guess because it has always had a high idle in colder weather until this year it doesn't. I am thinking it may be time to trade for a gas burner........

[dannyboy950]

Try checking compression for a start and take a look at my infomercial post, a few good inexspensive tests you can do.