Powerstroke loses power

[iscandan]

I have a 1996 Ambulance with the 7.3 Powerstroke Diesel which my buddies and I converted to a tailgating vehicle. It has 27k miles on it. Last year we took it to a diesel mechanic and had a general maintenance and it has been running great.

The vehicle sits for weeks at a time and is stored outside.
It starts right up. The other day we drove it and it would sometimes feel like it is losing power. It did not stall. It just would not accelerate when you gave it gas. Would shift it back to neutral and then back to drive and it would be fine. Then a few minutes later it would do the same thing.

We brought it to the same mechanic and he said it is the Injector Drive Module and wants $2200 to fix it. He said it is labor intensive to replace the module


Any opinions?