After the fiasco of checking the actuator wiring harness and having more problems after reinstalling, I solved the problem...

I bought another car.

Not to worry, I didn't give up on the 300SE. Just knew of a wrecked '93 at a repair shop near by. Called the shop to see about getting that part and the owner pestered me to by the whole car. I'd gotten some parts previously (trim items) off this car, and he'd wanted to sell it then for $2,000.

I paid $1250 delivered to a buddy's repair garage where I can have access to a lift for disassembly.

Pulled the actuator off, cleaned it up and installed it. Turned the key - no more full throttle blip at key-on. Buttoned everything up and took it for a spin - 5th gear is back, and so is the cruise control!

Pulled codes for the EA/CC, and still had the #3 error, but I think that was from the previous actuator. Erased that code. Code #6 is still there as well, so I'm going to check the adjustment of the neutral safety switch and replace it if required to see if we can get rid of the code. I erased the code and will check later to see if it comes back before I make the effort on the NSS.

This AM, I hit the same spots in the road that had previously plagued me with throttle blips - not a peep out of the "new" actuator.

So, my cost on a new actuator would have been $1524 with tax. The way I look at it, I'm already ahead to the tune of $274...

Best part of the deal - the car came complete with a newly rebuilt-by-Mercedes transmission with about 8,000 miles on it.

Never parted a car out before - now's my chance.

Thanks to all that have contributed suggestions to this effort.