Has anyone else have the problem here that I am? I’ve done both the medium, and both the hard difficulty V8 engines, but after about 6 attempts I still can’t complete the Cold Steel Taxi scenario. =\
Why don’t you check out the youtube video on that one then? Maybe you are missing one simple element of this scenario 
Here is the link: youtu.be/du8UH530Fng
Cheers!
Its not to hard at all. Im currently at the silver level working on making a gold engine.
It was super hard for me. I beat the 24 hour endurance scenario before this one, and in many less tries, lol.
My main problem is I was running too rich and with too much cam in every one of my attempts.