Changed oil, sluggish cold start.
 

The truck has been running really well, until this past week.

I usually run Ford Powerstroke (Motorcraft) oil, but Walmart was out of it, so, for the first time, i tried Rotella 15W40. I used to run it in my Cummins and never had a problem. Since the oil change, I have noticed that the truck sounds like it's being started on a bad battery. The problem is when it the truck is cold; once the truck warms up, it starts fine. Is this an oil issue or is something else starting to rear its ugly head? Any help would be greatly appreciated.

What oil filter did you use?

It could be, I noticed this exact thing when I went to valvoline premium blue 15w-40 from rotella 15w-40, the valvoline made my truck run much worse. However, a LOT of guys use the rotella 15w40 with good results, which is why I'm kind of shocked by this. The motorcraft is also a semi synthetic though, is it not? Where as the rotella is just a standard dino oil. Try the T-6 rotella, that's what I'm using now, runs awesome.

You might also try adding some rev-x bottles or evergreen.

The Motorcraft is a dino, also. I am using Motorcraft filters, as I have always done ... the only change was the oil. It seems to be fine, once the truck has warmed up, but that first start in the morning is a bit sluggish. I'll do my 3,000 miles and revert back to the Motorcraft. I used Rotella in my Cummins and never had an issue ... oh well, lesson learned.

Thanks for the input!

Which motorcraft oil were you using, they have a bunch of different diesel oils, including a full synthetic 5w-40.

I was using the dino that's in the orange labelled bottle. It's recommended for the Powerstroke. I've been using that since I got the truck and have had no issues whatsoever. In fact, the combination of the Motorcraft filter and oil had made an improvement to the starting of my truck.

I noticed very similar things when I went to Valvoline premium blue 15w-40 (not the synthetic extreme stuff), made my truck run like poo in the morning. These trucks literally tell you what they like and do not like!

Have you tried adding rev-x, or evergreen?

Okay, the wife drove the truck to work today, parked it, went to start it and nothing but a clicking noise. She got a jump start to get it back to our driveway, but once it was parked again, it will not start. I'm leaving work early to pick her up from work, then I'll be checking it out ... any ideas? Batteries? Anything else I should be looking at?

FICM??

No codes, so I don't think so. I started a new thread "No start" that has more information. I'm going to be replacing the batteries today.

You don't have to have codes to have FICM issues. 95% of the time you wont have codes in fact.