Help; Loss of power

Was taking the moho to a shop a few hours from home to get the A/Cs done.



I was unable to get above 45mph. Just had it out for a drive last week-end and it ran like a bat out of H.... I made it back to the storage lot.



Cummins 5.9 BTA with Allison transmission.



I checked all the fluids. Transmission was low and topped it off. Drained fuel separator, nothing noted.



Fuel filters are a year old with less than 100 miles in them.



Engine idles great and revs with no load just fine.



Any ideas before I call Good Sam to arrange a tow to the nearest shop would be appreciated.



I am going to crawl under and check the fuel line. There is not a secondary pump that i know of nor was one needed during the 1400 miles I have put on it in the last 15 months.



Thanks!

Dave