So my wife purchased this car but the gas pedal does not pop back so there is a rope tied to the gas pedal to throttle down the engine. Looking for any ideas on what I should be looking at to fix.
Thanks
steve
Probably missing the return spring from the pedal arm to an anchor position up under the dash.
Also check the linkage for binding.
I can’t find a ‘300SEL’ in '73. Is it gas or diesel?
Think “fastest four door car of the era”. It was the 300SEL 6.3 liter. I got to drive one once in about '75. Air suspension made even the worst bumps disappear.
Roadrunner’s advice is good. Better get it fixed before you hit something, as fast as that thing will go.
One thing to check on a vehicle this old is a frayed throttle cable.
If the strands of the throttle cable start fraying inside the cable jacket, it can act like a Chinese handcuff. That is, it moves freely in one direction, but grabs in the other direction.
Tester
it’s gas, it’s probably technically a late model '72 as they were only made from 71-72
She only got the 4.5 but that’s plenty big enough v8 for that size of a car 
Yes the air suspension is great, provided you let it inflate completely 
Well for the moment she’s not driving it until we can get this fixed and then get a good tuneup on it.