Hello Ya'll,

I have a 2000 Expedition, 5.4L with the 4R100 transmission that I use to tow a 6400 lb travel trailer. I bought the vehicle used with 27000 miles on it 4 years ago - it now has 73000 miles. The vehicle was previously used as a rental vehicle (did not find out till after I bought it).

My problem - it has always felt like the engine is missing when I accelerate from a dead stop when the vehicle is HOT only. The truck will accelerate normally then jerk, accelerate, jerk, etc until I am up to speed. I was told from a friend that it might be the torque converter. It is VERY noticable when pulling the trailer.

I have never got any codes for an engine miss. I have lubed the slip yoke thinking it is the clunking problem. I have installed a superchip and an ingnition boost from troyer performance. the truck still does it. I am noticing a loss of power as if the truck is not putting out its potential (seat of the pants dyno test). I have gotten comments from other people about the truck lacking power.

Could it be the torque converter? Transmission? any help is appreciated - thanks in advance.

God Bless
Jeff

 

How old are your spark plugs?

 

Plugs are brand new - put them in at 70000 miles along with a new fuel filter.