Hello,
First off here is the deal. We bought a 2001 Excursion yesterday with the 5.4L in it for one of our kids. Picked it up in Northern Az and drove it 240 miles home. Ran perfect the whole way. Get it home. Decided to rinse off the motor because it had a lot of red dirt on it. Every since then it has a miss here and there. I was scratching my head trying everything. I disconnected the cannon plug (?). The square box of with with the 10mm bolt. I blew it out. And now the A/C quit working. I took it out on the freeway and at a high RPM the A/C will start up for a few seconds. I took an air hose and blew out as much excess water that I could. Is there something in particular I should be addressing? Ive ran out of avenues and dont know where to go from here. This happened yesterday. This morning I fired it up and ran it for about 10 min and it ran perfect. Went in the store for 15 minutes and came back out to it running like crap again. ANY SUGGESTION'S will be greatly appreciated.

 

Not sure about the a/c. The miss sounds like you got water down in 1 or more of your cop's. Remove them and blow each hole out with air, and check the condition of the boots. Replace any that are not flexible like rubber should be, or cracked.

 

When you say 9ops what exactly do you mean. I'm mechanically inclined with good old fahioned motors. These newer motors I'm lost on. I appreciate your help.

 

COP or Coil Over Pack is that black box with the small bolt on top of each spark plug. I had the same problem with my 2001 V-10, I replaced all of the boots between the pack and spark plugs. A few months later the problem showed back up I purchased a cheap code scanner from JC Whitney which diagnosed a bad coil pack....replaced the pack and problem solved.

 

Thanks for the info. I'm going to do the coils tomorrow. I found the 1st plug coil plug had a lot of water in it. Maybe I shorted it out. Change them out tomorrow. Yay sounds like loads of fun but will repost then.

 

They're easy to change. 7mm socket

 

The A/c thing comes and goes. Ive changed plugs today, wires, and flip flopped a couple new coil packs in and still has a miss. Found some water sitting on top of spark plus but blew it out and changed the plug and still nothing. Going to shop tomorrow for diagnosis.

 

Apparently the "pressure washing" I did caused the #6 coil to short. Changed it out and ran like a champ again. Thanks everybody for your help.

 

I did much the same thing, got one of my Ex's a 2001 with a 5.4 4x4 while in phoenix. the red dirt was everywhere. So I blew out the engine, but then (thought I was careful) but I rinsed off the engine. With care of the COP locations. This resulted in a hard miss when cold for about 10 seconds when started. Ok, replaced all COP, spark plugs, PVC, and hose, complete tune up. Ran much better but will had a hard miss when starting cold for those first 10 of so seconds. Code scanner not too much help. The started replacing some of the injectors. Ok, that was not it. Took to the FORD dealership, the had it for some time, charged me over $475, and said I needed a new computer. Cool. I declined to spend the $1,200 there for the unit at that dealership. EX now ran worse. Would no longer run smooth while climbing the local grade hill.
Bought new computer, had installed at other dealership. Runs better, even better mpg and performance. OK, BUT still has had miss for first 10 seconds and then smooths out.
Soooo, what might I be missing here? Out of the 3 EX's that I have, this is the only one that does this and cannot find out why. Mileage is 120K