Kinda a long story I will make it as short at possible. My truck is 07 classic. Crew cab long box. All original unmolested. Just turned 134,000 miles. I'm from Northeastern Nebraska. My wife from southeastern Kentucky. We go there every summer to see her family. I got tired of hotels so I bought an old 33ft 5th wheel camper. Last summer at this time on the way home it was hot as hell. Around 100 degrees. We get to Bowling Green and all of a sudden I cant get over 2000 RPM and the check engine light comes one. We limp it to a dealer. They say injector pump is out. Fine fix it. Fast forward one year. 2 days ago. We are on the way home again. Its 98 degrees. 109 heat index. its hot so I set the cruise on 55. Same thing happens. Limp it to a dealer in southern Missouri. They run the code. Low left fuel rail pressure. They want to put on a new fuel rail. I'm thinking this is exactly what happened last year. I ask would bad fuel cause this? Yea it could. Well lets change the filter and see what happens. I pull my spare filter out. they clear the code and I'm gone. I have 3/4 tank of fuel. I get 45 miles and she cuts out again. I limp it another 40 miles to my buddies place and park it. Next morning it runs fine. Nothing wrong but the engine light is still on. We take it to O'Rileys run the code. Low fuel rail pressure. They clear the code and I buy another filter and 2 cans of sea foam. Just in case i got some bad fuel with some water in it. I didn't change the filter but I dumped the sea foam in and headed for home. 10 hour drive it ran great. No problems but the temps stayed in the 80s. Next summer Im going to Florida to see my brother. I dont want to fight this crap again. Ive done some research and some say it could be the fuel pressure relief valve. Im gonna pull that out and put in a plug. Im going to make sure the tank vent is not plugged. It could be vapor locking. I have a lift so that makes that job easier. What else could be causing this?