1997 5.4 Expedition bad misfire...HELP PLEASE!!

[craneop1994]

I have a 1997 Expedition 5.4 l 4 x 4 with 120,000 MI. The other day I drove it to the store it ran fine I came home when I went to leave again I cranked it and it was running terrible sputtering, no power, I hooked up the OBD2 and it gave me multiple codes p0351 p0352 p0353 p0355 p0357 p0443 p0705 p1401. I replaced all the coil packs and it didn't make it any better please help...

 

[ChrisOIFdoc]

Since it is throwing multiple codes, some not related to others, I would recommend checking wiring/ground/voltage issues first. Three of the codes have nothing to do with coils so that's where I would start checking for any wiring issues first. You may need to use You Tube for visual help in locating ground issues. DM a member called Bedrck47....He seems to be pretty savvy on steering people in the right direction when it comes to electrical problems.

 

[Bedrck47]

You state that you replaced all the coil packs YET you make no mention of replacing plugs or boots

 

[docraymund]

Check the egr pipe one early morning. Start the truck and feel if it gets hot after a few minutes. You may have a faulty egr system.

 

[Will H]

I would HIGHLY recommend replacing the factory ground straps with at least 8ga wire with compression fittings that you screw or bolt in place.

ESPECIALLY, if you have any type of aftermarket audio system amplifiers.

Those factory ground straps will cause all sorts of electrical anomalies once they begin to corrode.

Firewall to engine
Radiator support to frame
Body to frame

 

[ChrisOIFdoc]

Any luck?

 

[Richard Gibbs]

i had a similar issue and it was two cracked vacuum hoses... also replaced plugs and boots at same time.

 

[Lifesavr65]

Also had similar issue and found vacuum leak at 90 elbow by PCV valve.

 

[Misfit]

Throw some new plugs in it. That's probably a 99% chance that's what the problem is.

 

[craneop1994]

Changed the plugs and coil wires. Had someone listening and still terrible misfire. Che ked the egr vale all good. My brother noticed a noise when i turn the truck off. Also codes read misfire on 134and7 when you turn the truck off it sounds like a loose marble on the passenger side under the valve cover. Doesnt sound too good. So if anyone has any thoughts thanks in advance.