k7780446

But the shop said they checked them.

primalurges

Eyeball test can detect worn plugs but can't detect a defective plug and it absolutely cannot detected a bad coil. About 15 years ago my F150 back then a V6 had symptoms very similar to yours. Fortunately it was somewhere around 30k miles so I took it into the dealer. The problem turned out to be a spark plug that inexplicably went totally dead. Don't know what code it put out because it was under warranty so i never bothered trouble shooting but I do remember driving back home in a not of a panic because it sure felt like major engine trouble. Not too long after that I had a second run in where I clearly had not learned my lesson with a bad plug. After doing routine maintenance on my boat engine I started it as usually it idle normal everything seemed to be ok until I took it out a couple of weeks later. My boats top end was about 42mph. Well after the spark plug change my top end was like 20mph and I was like wtf? Long story short, I Swapped coils, went over fuel system took carbs apart and cleaned them and no change. I decided to start disconnecting plugs one at a time and that's when I figured out that my 4cyl 2 stroke can happily idle with just 2 cyl firing. I tries several two cylinder combination till I figure out a combo that would not hold idle. Turns out I had a defective NGK plug straight out the box. And lastly my 5.4 had a lean condition on bank once that turned out to be a weak coil. My symptoms were not as bad as yours it was just the occasional rough operation but unlike other bad coils that I've had, instead of getting a misfire code I was getting a misfire and lean condition code. Moral of the story don't rule out the cheap simple stuff. Try swapping your coils from one bank to the other to see if the problem changes side. It's a cheap test that will only cost you a little time and if you don't know the last time the plugs were changed I would change them because people tend to not want to mess with 5.4 plugs and leave them in there forever and very bad plugs will cause symptoms like your having which have to be exasperated in a forced induction engine.

k7780446

Going on a month of no truck

k7780446

Mechanic said after I asked if it was off on timing at all. ...." A little but we dont think thats the problem. There might be someing wrong with the lobes on your camshaft. Had alot of burning. Like oil wasn't getting to it. But we will find out the problem soon"


Any thoughts??

k7780446

...

k7780446

Well all internals, compression. Cams, timing chain , phasers in good condition. Sparks were pulled and all looked good.

They are gonna start looking at computers and electrical now as all the mechanical parts look good and don't have issues....they think the custom tune could be the issue?

Anyone hear of the tune being bad or something computer wise causing these issues???

They are slowly ruling everything out and it's a relief the internals and compression are good!
But it sucks I'm still out a truck and it's literally been one month and I've only driven the truck 3 days max sense I bought it!