On my way home from my first run of the season [about a month ago], I noticed, what seemed to be, loss of power around 45-55 mph and significantly at the 1800 rpm range. Also upon hill climbing [where I alsways have had a lot of power - even acceleration up-hill] and I also attempted to drive-up-on a set of step chocks a few weeks ago and seemed as-if it just didn't want to do it.

I am ready to head for the mechanic some time this week, but was just wondering if anyone had any suggestions ...if this is an engine or transmission problem. Tranny fluid was changed a few years ago and still looks good and does not smell burnt or anything and my trans temp gauge rarely warms-up to read anything, unless coming into town after a few hours on the freeway.

Coach power is good off the line and above 55 mph or above 2000 rpms and will top out around 75 mph ...it is just the mid-range where something is suddenly missing.

Sound to me like your secondary booster fuel pump
located in or around the injection pump itself. When it happened to my '91 Dodge/Cummins pickup the repair bill at the local Cummins/Onan dealer was about $300 (10 years ago). I had the symptoms you describe almost exactly.

Steve

Sounds like a turbo boost problem to me. Check all the couplings to the Air to Air cooler. What does your boost gauge have to say.

Gary Carter is the winner on this one:

ZERO boost...

Air Filter was soaked with rain water from a 3+ hour down-pour I drove-thru a month ago. Filter replaced. [needed to be replaced anyway]

2 Turbo Hoses Replaced.

Restriction in the muffler indicated. Muffler Replaced. Original Muffler.

Timing Checked.

Fuel Filters Replaced.

Inner Cooler Cleaned.

Boost Re-checked.

...everything is now good-to-go!

And a very good thing the Cruise Control is now working, as it is difficult to keep-it under 70.

...and no more BLACK exhaust!

Thanks for the help!