i have a 97 f150 that had the 4.6 and now has the 5.4(99),left the coil packs motor has been in for a year with no problems,ran great woke up one morning last week started running real bad,(rain and got real cold the night before)started missing and backfiring,i changed the spark plugs,plug wires,coil packs (used ford brand),checked all the fuel injectors and just installed a new crank sensor,seems like is running worse,and yes the firing order is right,took off the throttle body and cleaned the egr valve and throttle body,wasn't to dirty,broke off a egr bolt and had to tackle that prob,i'm stumped and running out of money,help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

No CEL?

 

check for vac leak usually with pcv hose and clean the maf sensor best i can say with what your saying

 

codes were egr and o2 sensor pass front sensor i think,going to retest tomorrow,no sounds of a vac leak

 

You need to post the P-numbers of the codes.

 

Yea, post the scanner #'s. There's more than one code (DTC) per valve/sensor.

 

p1451,0141,0401,0303,00304,0307,0308,0174,then they repeat,i cleared all codes sratred truck for 10 min and retested,p1451 came up again,evap vent control valve,could this be the prob?

 

truck does have 290,000 miles on her,installed 5.4 last year along with tranny,then transfer case,but other componets are at milage stated,the 4.6 lasted to 279,000 miles then started to nock,she still looks good and runs 315's,i am greatful for everyones input for helping me resolve this problem,thanks,i never get tired of defending our blue oval,rob

 

You do have an issue with the evap system. Get that cleared first and see where you stand.

P0141 is no big deal, that's a bad downstream O2 or a wiring problem to it. It won't affect the way it runs. P0401 is an EGR problem - clogged EGR ports in the throttle body, vacuum hose issues, or a bad DPFE. P0174 is a lean code, fixing the evap and/or EGR may clear that, or you have a vacuum leak. The 03xx's are cylinders that are missing.

 

What Ford brand plugs did you use ? Somethings going on..(?). Double check your work with the diagram below, - just make sure. -


---Firewall---

--Front End--

Firing order ~ 1,3,7,2,6,5,4,8

 

ok today i replaced switch above fuel tank,and replaced switch above brake booster with the green,white hose clamps,nothing changed still the p1451 code came back on,i've checked the firing order still missing on 3,4,7,8 and running bad,cannot find or hear vac leak,unplugged vac line at egr nothing changed,unplugged wires to the switch near the egr valve that has the two lines going to it from the exhaust forget the name of this switch,and hoses seemed find,what the heck is going on with this ford? also i used motorcraft plugs

 

Bad coil pack. the one that fires 3,4,7,8 just saw jbrew post looks like there isnt a common coil pack must be something else..

 

no other help or input,i need to get this truck running,i just need to figure out the misfiring 0n 3,4,7,8 i could give a @#%^$$@$ about the emission codes right now

 

figured it out on my own,guess i get back to my 67 camaro 427 project

 

enoy yourself