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I have a 2000 expedition 5.4L with 52k miles. I recently had the tranny fluid serviced and have never had a problem with my SUV. Recently I have noticed especially when it is hot outside, the car sputters and surges (loss of power) anywhere in the low rpm/low speed range. Almost like it is getting a lack of fuel. The car idles fine and I have had no engine lights come on. After searching this forum I have narrowed it down to a bad COP??? Does that sound like the case? If so, what is the best way to figure out which one is bad? Better to replace yourself rather than having a dealer do the work?
Just to add to my post, sputter was not the correct word. It is more like a hesitation feeling. seems to be from start to around 40-60 MPH. With no engine lights coming on can you stilll diagnose the problem if it is a COP?
I replaced the fuel filter two days ago. Maybe a little change, too hard to tell. It's weird it seems to run fine when the outside temps are below around 85 degrees. I really notice it when it was 90-95 out. It mainly happens when your taking off from a start or accellerating from around 10-40 MPH. Seems to kind off like it is missing or lugging but with no weird noises. I pull a pop up tent trailer, and some times from a rolling start it feels like I am pussing the pedal to the floor to get the expy up to speed. As to the previous post, starts fine with no surging forward or hesitating when I put it gear.
I would never say deffinatley coil(s) but that sounds Exactly like my symptoms we had with our Expy. Have you or the dealer recently washed the engine compartment? water and cop's dont mix at all. The dealer detailed mine before I picked it up and ended up replacing all the coils withing the first 2 weeks I owned it, and i never had a problem since. And I drove it from Boston to Alaska after the coil replacement with still no issues. do a search for "how to test COP's" I remember seeing such a post but did not pay to much attention to it because mine was warantee work
I am having the exact same problem. Would love to just change the spark plugs, but what a job! I was thinking I would first try the fuel filter and if that doesn't do it I will probably have to bite the bullet and do the plugs.
It is funny you mentioned the wash. About 4 months ago I washed the engine with Simple Green and then sprayed it off. I have never had a "check enginr light" come on. Would it come on if the COP was bad?
I would be very interested in hearing the solution to this problem. I have the exact same thin happening with my 2001. Runs great when its below 95, but loses power off the line when >95. It also sounds like it is suckign a lot of air throught the intake. I tried the fuel filter, put a K&N on it but still the same problem, These were things that I was going to do anyway so I thought I would do them before taking it to the dealer.