My father has recently fallen upon hard times and checked into rehab, while gone I have been tasked with taking care of his 04 ford f150 5.4 triton. When I got it there was a jiffy lube sticker that was 1k past the recommended service interval and I felt as thought the engine was louder/rougher sounding than most of the other 5.4s I have been around. After changing the p/s fluid and flushing the brake system, I changed the oil with some 5w30 Castrol Magnatec and the sound/smoothness of the engine has drastically improved. The truck technically specs 5w20 but it also has 200k miles on it and I know he hasnt been particular with the maintenance with it. I have seen some debate on using a thicker oil but in this case it has seemed to help. What do you guys think? The last thing I would want to happen is for his truck to start having trouble once he gets back.