Good day all,

For Christmas it looks like im getting engine repair work done,

Here is this wonderful 5.4 's issue now,
sometimes it will idle rough, sometimes it wont. sometimes it feels like it wants to stall, other times not. if im driving about 30mph up a hill around 1700 rpm, the engine feels like a bucking horse, it will kinda want to produce the power, but cant seem to find it till the trans drops to a lower gear. With this engine power loss is unacceptable because it came out of the factory with no power, i cant afford to loose more.

there is no check engine light. its been doing this on and off for a week. i dont drive it much, may 15 miles a day. i thought maybe it was bad gas , i had it sitting for a month, but since then ran almost 2 tanks of gas through it. Seems to act the worst when driving it, then letting it idle for 5 mins, then drive it again, that's when its very noticeable. no smoke from exhaust, no mixing of oil and anti freeze, plugs are a year old, filter is new.

opinions ? thanks guys

 

nobody has had this happen before? i knew this truck was cursed.

 

sounds like a misfire. hook up a scanner to it and see what codes you get.... could be a bad coil.

 

that's just it. its not showing anything.... it kinda seems like a bad coil, but short of replacing all of them, id rather not throw parts at it and still have the same problem

 

check this thread out.... another 5.4 guy having the same issue

https://www.ford-trucks.com/forums/1...nder-load.html

 

ill have to check this out, thank you

 

I'd start by cleaning the IAC.

 

Do as redford said. Personally I would try some seafoam through the brake booster line.

I would also clean the MAF sensor with MAF spray.

How is your battery and alternator?

 

Sounds like fuel related and not ignition. I would not replace the coils!

 

fuel filter seemed to have fixed it. thank you guys.

 

oh well. after 3 days i thought the fuel filter was my problem, it was nasty so i did myself a favor regardless, but my problem is back. ill have to clean the MAF and IAC.