Well i just picked up a 99 f250 superduty with just over 87K ...took it out this weekend towing my trailer and first few hills worked great. Then all of a sudden no power..missing and rough running....thought maybe a coil..found a new one at NAPA...then tried to figure out which one was bad if any? Not really sure if that is what it is..no check engine light till on the way home...100 miles later ...Anyone have this issues? 5.4 V8...and how can I check to see what coilis bad ?

Also on a another note...I plugged in my Rv trailer connector to the factory harness..and got everything working exceptor the charging line..Any ideas why the charging line may not be working..all fuses that Ican see are in...isthere a missing fuse box or something....

Thanks in advance.., Robert

 

hi. again I take it no one has any idea why it's missing?It is missing through the entire range..but more noticeable in the low RPMS..I gonna try to change the spark plugs and someone mentioned the coil packs...anyone know how to test them to see if they fire? I'd like to get eth car going..thisis my spring break adn my kid adn I are stuck at home...good and bad I guess...thanks, robert

 

The first step would be to have the code read to help point to adiagnostic direction, for a specific cylinder misfire code.. The 5.4 has COP (coil on plug) ignition and doesn't have coil packs.. Some parts vendors will read/scan DTC's for free.. It may shorten your search if possible to retrieve the code prior to any work..

 

just got back from Autozone...and it read misfire at cylinder 3...and I have the coil on plug...ready to go..I still have one that I did not replace..So I am going to change it..anything else I should do while I am at it?..

Also thanks for the reply, Hayapower ...you seem like you are the go to man here..kind of like I am on the Socalsvriders board

 

You've changed 6 outta the 8in 87K?Sounds like you had a 50/50 chance of being correct!! But you never know Your rolling up on a change interval for plugs so this might be the time since your pulling a few COP's anyway.. Also, if you have any doubt about a failing/failed COP, swap it's cylinder postion and see if the misfire code follows the swap..

 

yeah just going to change #3..funny it was just changed before I got the truck a few weeks ago..number 3 according to my book is passanger side third one back correct?

 

Correct..

 

Ok bosch plugs must be crap...or something else is going on..the plug got pulled and the lower electrode was cracked... and covered with quite abit of oil..or fuel not quite sure..changing all the plugs to see what else I see...btw since I have not had an old truck in some time...would it be wise to invest in one of those scanners and what is the most relaible accurate model ? Thanks..

update: put it back togetherand still have a mild miss...could it be that I had the battery off? and it( the computer)is still learning?

 

Oily carboned, or just wet?
Do they look like they've been run for a 'good long' stretch or newer install failures?

You can by a code reader dirt cheap, but they don't have any advanced diagnostic capabilty.. You might be able to find someone selling a scanner that needs an update but still current to your truck so you have the capabilty torun self diagnostic tests/scans, access parameter info display, troubleshooter/DTC info.,as well as some component tests..

 

No...

Are you able to comp test that cylinder for any base engine problems? Could be fuel/coolant related if it's cracking electrode insulators, but a comp test might be good idea straight off..