I picked up a 2004 f150 in an auction with the 5.4 vin engine code 5. 190k Miles. Body and interior is mint. The engine not so much... runs very rough. Right away it seemed could be a plug or coil. Replaced plugs. And initial coil that it thru code for. No change. It then threw codes for cam phasers, oil control valve, tensioner, and timing... Cleared all codes drove it a bit again and came back with a coil code again... I am very mechanical and have a decent working knowledge of things. But with this i admit im a bit of a nubee. It runs and drives. It doesent have the accelration it should and at idle it shakes pretty bad. I drove it an two hours home and it seemed to run well at freeway speed just not there when you hit the gas. Any help would be much apreciated! So PLEASE HELP! Do I swap motors or get into the timing chains tensioners and phasers? Would the coils make it code out for the other stuff or is it only the other way. Timing would code coils?

 

With that kind of mileage I'd have replaced ALL the plugs AND all the coils as a first step to troubleshooting this issue. I know people try to save a buck (I do to) but it's easier to start with fresh parts. Do the basics like 1) clean the MAF sensor 2) clean the throttle body 3) check the FPDM to make sure it is serviceable 4) change all plugs (I see that you did already) 5) change all coils 6) new oil and filter 7) new ATF and filter 8) do the computer relearn process 9) make sure the foam around the air filter is in serviceable and working condition.

 

Thank you FX4Frenzy. That was my first thought (all new coils also.) Cheep to do... thanks again for the other sugestions. After clearing the codes I have been driving it a bit. It seems to run fine at times... tonight it sat at idle with no shake and barely any noise. On the highway it would dog getting on the gas. I let off press the gas again and the engine reacted. Still felt as tho it was a miss. Letting off about 45 it would get the shakes. Its not a constant.

Researching the coils... dg511 vs dg508 then there was a fd508 I think? Looking at the comparetive chart fd508 n the dg511 were interchangable the dg508 was dif. Omly dif I saw was one had a slight dogleg to it. Any insight into this so I can get the correct/best ones ordered would be awesome?

 

You need DG511's.

 

Is that a trusted brand glc? I had bad luck with a cheaper brand of coils, and ended up buying 8 new motorcraft coils