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Hello everyone, this is my first post, wish it could be on a better note!!
i have a 2000 excursion 4x4 v10 with 90k. The past few months ive noticed a tug or miss fire at low RPM(2000 AN UNDER) the past week its gotten worse, some ocasional rough idol and the missing is getting worse. Any ideas on whats wrong?? Any help would be greatly appreciated, i dont want to take it to ford yet!!!!!!!!! PS: NO CHECK ENGINE LIGHT YET
Classic bad 'coil on plug' COP scenario. Do a quick search on COP - with a half hour of reading you'll be ready to fix it. Agree, stay away from the dealership.
Last edited by wpnaes; Jul 12, 2011 at 11:00 PM.
Reason: on vs. over
Could just be water down in the boot. Mine ran rough and I just pulled all the boots and I had water down in 2 or 3 boots. (No bad COP) Blow them out with air and let them dry. Use plenty of dielectric grease when you put the boots/COP back in to help prevent moisture later. Also since I was pulling all boots I changed plugs too. At 75k my plugs definately looked like they were in need of changing. Might do that while you are checking.
Sounds like water down the hole to me. I replaced all my boots and sealed the tops with heavy grease a while back and those problems are long gone. I never have had a bad cop. (They are not playing good cop-bad cop). All you need is a tiny bit of grease on the spring end to keep it from corroding. Once water gets in there dirt and junk settles in and your boots go south.
My next thing would be to replace the fuel filter. It is possible that you either got a bad COP, didnt quite get one seated right, or forgot to gap a spark plug. However, of your problem is exactly the same, I would loom elsewhere begining with fuel filter
One of the tests you can do to try and set a misfire code is to get up to 60mph and take your foot off the gas and coast down to 40mph. Repeat as many times as you can. The deceleration tends to exaggerate any misfire issues you may have. I have a slight miss at idle with all new plugs and boots and haven't found it yet and cannot force the check engine light. I've used my Modis scanner and it shows no issues on the cylinder contribution tests which normally will detect the misfires as they happen. I've cleaned battery connections and all grounds. The Expedition has had issues with the 5.4 where the engine harness was routed near the ac accumulator which caused weird issues but we don't seem to have the same problem. If anyone has any ideas I'd love to hear them.
My next thing would be to replace the fuel filter. It is possible that you either got a bad COP, didnt quite get one seated right, or forgot to gap a spark plug. However, if your problem is exactly the same, I would look elsewhere begining with fuel filter
The fuel filter was replaced 3 months ago. After doen boots and plugs yesterday and it still running rough/bad, i put some STP Fuel Injector cleaner in with a half tank of 91 and drove it for 20 miles, came home parked it, an hour later took it for a hot lap and she runs like new and has since!!! Thanks everyone for your help!!! Pics come soon to the Ex w/trailer gallery!!!
Ah, well the bit about the fuel filter would have been good to know in the first post, haha. In the future, try running some BG44K or Seafoam through, instead of STP. The difference will likely amaze you.
I chased down a miss for over a month. Seafoamed. Air Filter. New Boots. Gas filter. Finally threw a code. Output speed sensor. Replaced it, no difference.
Bought Auto Enginuity software. Found misfires in Cylinder 6. Replaced COP on that cylinder. Just got home from a 300 mile camping trip towing a 5K trailer. Damn truck never ran so good. Without trailer I was averaging 14 MPG, I've never seen that. Sure it's combination of things, but a bad COP certainly made my V10 run like crap.
One of the tests you can do to try and set a misfire code is to get up to 60mph and take your foot off the gas and coast down to 40mph. Repeat as many times as you can. The deceleration tends to exaggerate any misfire issues you may have. I have a slight miss at idle with all new plugs and boots and haven't found it yet and cannot force the check engine light. I've used my Modis scanner and it shows no issues on the cylinder contribution tests which normally will detect the misfires as they happen. I've cleaned battery connections and all grounds. The Expedition has had issues with the 5.4 where the engine harness was routed near the ac accumulator which caused weird issues but we don't seem to have the same problem. If anyone has any ideas I'd love to hear them.
I changed my plugs and coils last summer, it ran fine. Just a week ago had a very bad mis when driving out of town, thought maybe bad gas drove 1200 miles and 2 tanks of gas- that`s not the problem. Put in 2 cans of sea foam and half tank of gas ( i run 87 octane) got it up to about 60 or 65 and let it coast down ( just like you said) and it worked. Did it twice.