So I've been having this weird issue lately with my 05 F150 5.4. It's been going on for a few days now. Everyday I leave for work she'll start up nice and fine, idles smooth at around 950 rpms. Ones I get going for the first couples miles it'll shift smoothly and all is well but once it shifts at around 50-55mph at around 1900 Rpms and drops down to around 12-1300 Rpms after say 5 miles or so, it sorta bogs down like it wants to stall. And it'll continue doing that until I get to where I'm going and turn it off. Then it's the same issue over and over again. It almost felt like the same issue I was having when I replaced the vvt solenoid and cam sensors. But this time it just feels like it loses power and doesn't want to go anywhere. But if I lay on the gas a little it clears up and goes. Doesn't hard shift or anything. Could this be a plug or coil issue maybe? Or maybe a plugged converter? No CEL or codes popping up either. Does also have a slightly rough idle after driving for a bit.

 

Can I ask what type and kind of motor oil are you using?

 

I am using Valvoline Full synthetic. 5w30. Was told even though it calls for 5w20 that 5w30 is okay also and helps quiet things down a little bit.

 

The reason I inquired about the oil was there have been problems with not using the recommended oil. Consider trying the owner's manual choice and see if it helps the VVT system.

 

I will be due for an oil change here soon so I'll go back to the 5w20 and see if that helps any. The issues just started a few days ago and I replace the vvt solenoid a few months ago so I'm sure it's due. Maybe I'll pull some plugs and see how they look. Truck had had plugs replaced before so hopefully they come out easy. I did have to replace a coil back in November also. Just crazy cause it's not throwing any codes.