First off its a 2006 F150 king ranch with the intercooled roush kit and roush tune. Last couple weeks its progressed from a slight stumble on start up, to now after its been off for a few hours it may start and run rough for a second, or, it may start then die, and then have to crank for at least 5 seconds before it starts. After it starts it seems to run fine. I downloaded the torque android app and did some data logging. Can you learn anything from the long term fuel trim? Any help is appreciated.

 

.......... .........

 

It could be anything from an open injector to a bad fuel regulator. You need to take it to a shop and let the mechanics test the fuel system.

The hard start and long start are both classic symptoms of a bad fuel pressure regulator.

 

I think I might have fixed it. Couple days ago went to start the truck after work and the battery was dead,the temperature was in the teens to low 20's all day, and the battery looks like the original from 2006 so I jumped it and went and got a new battery. I think that was my problem, fired up quicker than it has since I've owned it and the LTFT's were back to 0 on both banks. It even seems to run a little stronger. I dont know it the old battery was just to weak to completely burn, the fuel with the and colder plugs or what.Where is the FPR? I assume its on the fuel rail but I don't see it. Is it on the same side as the fuel pressure sensor? Its been a few days now and no codes,and no hard starts. Could it really have been the battery? It always cranked strong, kinda weird.