Diesel Surge

[T23Guy]

Ford Excursion With 7.3l Diesel
1. When I drive down the road at about 35-45 mph the engine surges. It lasts for less then a second but continues to do it at that speed. The engine idles fine and does not seem to do it at other speeds. The transmission shifts out fine. If it was a gas engine, I would think that the injectors were dirty and needed cleaning. (first diesel own)
I have purged the system for water, changed the fuel filter and tried buying fuel at other gas stations but the problem persists.
If it is dirty injectors, what additive do I use to clean them?
What else could it be?

2. Another problem with excursions is the door ajar warning light stays when the doors are all properly shut. The switches appear to be fine. Any fixes for this?

Thanks.

[jcs]

I don't know about the surge but i do know if you lube the door latches with some WD-40 and open and close the doors a couple of times it cures the sticking switch inside hopefully someone else can help you out with some more info