Can I get some help please? I am currently pulling a trailer through Joshua tree and I am stuck at the moment. Getting codes 304 and 316 on the truck. F150 2004 5.4 4x4. Replaced the coils and crankkshaft shaft sensor already today still no go. Any ideas on what to do next?

 

Are you still getting the same codes?

 

Try a set of plugs.

 

I changed plugs over summer, even moved plugs around, as well as coils, codes I do get are p0304, p0305, p0308, p0316, even got p0174, this thing is a mess. Clean out battery, cleaned out mass air flow and intake body, waiting for compression tester, looking at fuel injectors now

 

Still getting the same codes. Removed and cleaned injectors and a mess of sensors. Still the same codes. Truck runs ok by itself to get home but under a load with the trailer, no good. Could this be a compression problem?

 

No. The codes show a misfire in #4, 5, and 8 cylinders. P0316 is a misfire detected on startup and P0174 is system too lean bank #2. Given the age of the truck, I'd check out the fuel system. It could be that the fuel pump or driver module are starting to give out or injectors that are going bad.

 

+1 Also the fuel filter...

 

3,5,& 8 could have low compression which would cause those codes, you need 3 things to work air, fuel, and fire

 

I am currently having the same codes and issues as you had. What ended up being the culprit?

 

prolly no answer, 3 post 12yrs ago and hasnt been back. Have you checked any of the suggestions above, like fuel pressure.