Only when it rains my 03 Expedition will have multiple misfires I have replaced the coil packs on all of the cylinders but number 3 & 4 seem to have misfires when it rains. ANYONE have any ideas??????

 

any codes? check engine light flashing??

water in the air cleaner? check your air snorkle.....

 

check engine flashes then stays on. codes are usually ( multiple misfires cylinder # 3,4,8) and today the code was lean bank 2 misfire cylinder 7. It always seems to be something different every time I check the codes. Beginning to think 5.4 Triton SUCKS!!!

 

check charging system flashes on and battery light stays on. I replaced the alt. and the battery terminals June of last year and every since the batt light stays on and the info center reads check charging system, the alt is putting out 13.98 and batt stays at 12.98 any ideas?????

 

I had a similar problem when it rained in my Thunderbird....check air filter has not gotten wet...would make MAF read incorrect value and it would chug and bog every once in a while............

lean bank 2 could be clogged fuel injectors that side....bad O2 sensor on that side....leaking intake on that side....

multiple misfires? check the plugs for wear or fouling...

alt should put out a volt or two more than twelve...thats normal....


since you are having all kinds of random codes....perhaps its a PCM.....

Im just saying...check the basics and then bite the bullet........

 

I have gotten the skip to stop now. Bad o2? No had that replaced with the new cats about a month ago.New plugs,new air filter, had alot of these things checked when in shop last month. Thank you for all of your input I now have a few more roads to travel to get this fixed.

 

As much as I love my Expedition, I hate the SOB. I've had mine since new (2000 EB 5.4 4X4) and for the last 4 years I've been having PO304 (No.4 misfire) here and there, and most of the time when I'm travelling, pulling a trailer of course. I've changed No.4 COP twice and had it to FORD many times. They could not tell me anymore than my OBDII. One time they replaced the fuel pump (that was expensive, $900+) seemed to work great for 3 months and you guessed it, its back. I had a No.7 plug blow out a couple years ago, so when that was repaired I had new plugs installed then. only has about 8000 miles on the plugs since then. I just dont know where else to go because when it's running right, it's a beast. One thing I have just noticed this last time, it started to misfire while travelling uphill. so makes me wonder if some moisture is dripping into or onto No.4 and perhaps thats why it doesnt show up all the time. Just food for thought.