99 Expedition running rough after dead battery
 

Hi-

One night the Acc. was left on in our 99 Expedition and it killed the battery. I jumped the vehic. and it started. I was camping at the time and towing 28'er. The vehicle ran extermely rough while towing. When I reached my destination about 2 hrs. later, I disconnected the battery again hoping the computer would reset itself. I then drove the vehic. about 15 miles (without trailer). This made a great improvement, but it still "bucks" going up some hills.
Besides taking it somewhere for a ECC diag., is there something else I can try?

Thanks in advance

Kenny

99 Expedition running rough after dead battery
 

Your vehilce needs to "relearn" your driving style. My truck has had some quirks after disconnecting the battery. Give it some time, the problems should go away. Also, get your battery tested, if it is weak, that could have some adverse effects on the trucks performance as well.

99 Expedition running rough after dead battery
 

Thanks Rtpjunior,

The vehic. has been used for over a week and the problem still exists. I guess my next move is to disconnect the battery once again and start over. I suspect the issue is that I have put more miles on it towing a ~7000lbs. trailer than I have driven it without.

Thanks again...

Kenny

99 Expedition running rough after dead battery
 

That doesn't sound right. I've reset my PCM many times and sure it runs rough for a few minutes after, but never more than a couple stops and starts on the road. Have the battery checked at a Sam's Club. They have an awesome tester.

99 Expedition running rough after dead battery
 

Thanks for the Advise... After a 400 mile trip with intermitent rough engine stints, I bit the bullet and took it to my old friends at Lacy's Ford Lincoln Mercury in Catskill, NY (Great bunch). It took the Tech a few hours to isolate the problem down to a "intermitently bad coil pack" on the 4th cylinder.

Now I need to try to relate that to a dead battery. I'll take one shot. My battery went dead when the key was left on in the "Run" position. I remember the old days when this would cause you to burn up points and continually send high voltage to whatever spark plug the rotor and cap were poining to.
Is it possible that the same thing happened here? Does the PCM send a signal to the coil pack even if the car is not running?

Anyway, my Expedition is back to normal.

Thanks again,
Kennyiii_65

99 Expedition running rough after dead battery
 

It's very possible that the heater hose poised over cylinder 4 is leaking slightly. Antifreeze dripping on the coil pack would kill the pack.

This is a fairly common problem.

99 Expedition running rough after dead battery
 

Hi Kenny, Thanks for your post. I also have a 99 Expdtn. The very same thing as happened to me. My daughter left the key on and killed the battery. Has been running bad ever since. I have not changed anything yet, but your post has given me hope. I have read several of these forums with all giving different solutions. Our stories are very similar. Thanks again, Ken