There's also one manufacturer that experimented with (or produced?) a force feedback system that pushes the pedal back at you. Why it had to be an active system instead of a spring, I no longer remember...

If you're thinking of the one from Nissan, it's linked to a system that estimates optimal fuel usage based on the conditions.

That's the one. Good job finding it. :thumbup:

Well I have a rough outline of the mechanism. A pivoting arm will be held against the gas pedal arm by a very light spring. There's a solenoid operated brake on that arm to hold it in place and keep the gas pedal from retreating beyond that point.

Now I just need to figure out all the details. Only two big ones: how to mount it so it can be removed quickly (warranty) and how to implement the brake. I need a system that I can be very confident will never lock up. That would be bad.

I took a look and things are pretty tight under my dash around the gas pedal. I'm not feeling very confident I can come up with something that'd be easy to build and easily removable. I could fit a spring in, though, so maybe I'll try that simple system. I don't hold the pedal down for long periods anyway.

It probably is possible, but it is not the most efficient way to drive.

There is a difference.

Cruise Control.
Cruise control has always been meant to keep an assigned speed.
Cruise Control has worked off the speedometer or, now that everything is electronic, the computer.
Because the computer is in charge, the engine always runs optimally.
Once, it was inefficient MPG wise but now the computer is so good there is little difference between the MPG the vehicle gets by itself and the driver's foot.


Hand Throttle.
The hand throttle works by holding the throttle at one setting.
Vehicles started out with hand throttles so the driver could keep them running while using the choke while the engine was warming to operating temperature.
Hand throttles were useful to keep speed.
And also, in the case of utility vehicles like the Jeep, to ford deep water and keep the feet off the floor and from getting wet, also to run the PTO and drive pumps, saws, drill rigs and all the other tasks that could be dreamed up for them.
The drawback of the hand throttle is that the engine can run outside it's performance envelope in hilly country, racing and lugging, neither of which does any good at all.