My truck is showing code p1277. The only time I really notice anything is cold mornings like we been this week. Low 50s. When I first start it in the morning the engine light goes on and off until the truck is completely warmed up. Any ideas? Could it be the injector going bad?

2003 f250
7.3 with 415000 miles. Stock injectors

 

I think you are looking in the right direction, especially with that mileage on the injectors.

High to Low opens can be caused by armature plate clearance too tight from worn poppets. Some times you can get the suction issues to get better for a little while with the use of synthetic 5W-40 oil, but I think you need to look into replacement(or rebuilt) injectors before too long and cold temps.

 

What Alan said. That is a lot of miles on the stock sticks. You should look at it as a blessing that they made it that far. Mine started giving me problems right around 150,000 miles. You might get a few more months out of them going to synthetic, but it will get harder and harder to start if you aren't plugged in.