I recently bought a 1997 F150 with a 5.4L engine. Before I bought it, I took it to my mechanic because it ran horribly. The car dealer said that 2 other mechanics had looked at it, replacing all plugs, the coil packs for 1 & 7, and they cleaned the throttle body.

My mechanic ran it through his diagnostic tool and said that there were misfires on 2, 4, 5, and 8 and that the coil packs needed to be replaced, so I decided to buy the truck and do the work myself, since the dealer gave me a deep discount on a truck he couldn't fix.

I replaced coil packs on 2, 4, 5, & 8 and it still runs just a bad as it did before. I also replaced a couple of hose, just to make sure they weren't leaking. At one point the CEL indicated there was a problem with the DPFE/EGR valve pressure sensor. I checked the hoses and put WD-40 on the connection. Since the miss is solid (idling or not), I assume the EGR valve is not the issue. The CEL is on again and it says it is misfiring on 8 now.

Any suggestions on where I go from here?

 

Welcome.

What is the condition of the spark plugs? Last time they were replaced? Condition of the plug boots? Was dielectric used?

For starters .... until you-know-who arrives ...



MGD

 

The plugs were supposedly replaced before I got the truck, no more than a month ago. I replaced 4 of the coil packs, which included the wires to those cylinders (2,4,5,& 8). Not sure about dielectric (if it's the grease that goes on the boot and the connection, yes). I plan to remove the plug in cylinder 8 to visually inspect it, since it gave the latest misfire reading.

 

Pull everything, replace the plugs with Motorcraft, and replace all the coils with Motorcraft or Visteon.

Note - when telling us you have DTC codes, please post the exact P-code, not what the interpretation is.

Motorcraft SP-459 plugs - $4.31 each at rockauto.com, no antiseize, torque to 28 ft/lb.

Coils - http://www.ebay.com/itm/New-Visteon-...3989cc&vxp=mtr

Dielectric grease required, in the boot but *NOT* on the connection.

 

Not again, -crap, I need a raise.

Well, need the exact EGR dtc, as that could determine where to go next.

 

^^LMAO !!!

Done! It's in the mail




MGD

 

That's cool! But auh, don't you need an address first ?

 

It also sounds like someone washed the engine and done so VERY wrong. That's not hard to do wrong.

 

Hell no - ever'body in the Post Orifice know y'all!

Mr. Joey Jbrew
Podunk, Michigan
U.S of Eh!
Zip = Yep

< White REAL clean F150; likes BBQ >




MGD

 

And takes in female sword swallower's.

No one is going to get that...Cept you

 

Yep - me ... and the 3,000 other folks who pissed themselves reading that thread


MGD

 

I got a code P0308, so I removed the plug for cylinder 8 and it looks new (and it's a platinum Motorcraft), as I was told by the dealer that sold it to me. After driving it some again, the CEL went off again and now it says it's a P0301. Since it seems to be moving from cylinder to cylinder, I suspect that it's bad gas or something (I know I putter when I have bad gas). I put some Berryman's in it and filled up the tank. I plan to drive it to see if that's the problem.

 

Ditch the Berryman's. Run Techron only (or Gumout with Regane in a pinch).

And post those EGR DTC's Jbrew asked you for.

MGD

 

Yea, I'm not sure he needs are help, - it may be for naught doing so. At least it looks like it's going in that direction.

What can you do ?

 

Have you Pressure washed the engine? I quit washing my 5.4 because it always put water somewhere causing a miss on no. 5 cyl. Just food for thought...