All,
With help of many on the site I'm on my way to a repaired air throttle system. I installed an electronic cruise control and the installer said he had to cut the accelerator cable and splice it, (with an electrical butt splice...). The cruise works well, but on my examination of the install, I didn't like the butt splice, and the coach wasn't going full throttle and needed to be adjusted. While adjusting the butt splice failed. I tried to remove the air cylinder that controls the acclerator cable to the engine and when turning the nut that is the end of the cable to remove it the mounting tabs on the air cylinder broke off. I'm driving to Scottsdale AZ this Saturday....
I posted my problem on another thread and got great data: I had my mech U bolt the accelerator air cylinder to the bottom of the engine compartment in lieu of no mounting tabs and the mechanic ordered the cable from Spartan: $325 plus shipping. The air cylinder was $275, so both were $600 plus shipping. In looking for a work around I found this company:

http://users.cwnet.com/thall/airthrottle.htm

If you with an air throttle will look through here at the bottom of the page is a 'General Purpose Throttle Control' throttle cylinder at $201 I am quite sure would replace my air cylinder AND cable as no cable is required, just a threaded rod. The Transmission Modulator for $91.00 would also be required. A mounting bracket must be fabricated, but for a savings of $300 I think it would be worth it. As well these units are being made today. These are universal units and sold as well to control explosion proof equipment on oil rigs.
I am in a hurry or would have taken this route. I am not using the Bendix cruise control, so the potentiometer is no longer required.
I wanted to pass this along, the company also sells accelerator pedals. The tech fellow who answered said that he sends the accelerator cylinders out for all makes/models and has few returned as incompatible due to the ingenious linkage it has which is adjustable to various distance throws.
Thought I would share. If my air cylinder goes out or my pedal, I will buy from this vendor. I have no association whatsoever with this vendor, just trying to give us some options here as these coach's age and Spartan/Gillig sell NOS parts priced at their weight in gold. As well at some point in the future they will no longer be available....