I have a 1983 240DL with a 4cyl w/167000 miles on it. it was running great with no problems then one day i was on the freeway and the car kept accerating out of control i put the car in neutral and it rev up really high so i shut it off and costed to the side i was right by my home so i had AAA tow it to my home. It starts and runs great but it revs like you have you foot on the floor. I have replaced The ECU, all vacume lines, cap, wires, it has a new battery i have owned the car for years and have had no problems with it at all, Except for the light switch breaking and i just replaced it. Does anyone have any suggestions What could be the problem?

 

I also replaced the fuel injectors with in the last 500 miles.

 

throttle position sensor?

 

sticking throttle linkage or throttle plate...clean them out really well and make sure the throttle cable isnt sticking

 

Check the see if the wire on the idle air motor is loose. Mine did the exact same thing and it was just a loose wire. As soon as I pluged it in the engine ran normally.