Car went into what felt like limp mode yesterday. No acceleration or kick down. Today, my local garage (not Merc experts I don't think) came up with fault code 2513-001 which indicates a problem with the inlet port motor. The garage cancelled the code and said to see if it returns. Car was just the same as I drove home so it is something which is not just going to go away!. This seems a fairly common problem and to be honest there seem to be lots of problems with Mercs for so called quality cars (this is my first and probably my last Merc). Anyway, I think there are several possible causes - what is the quickest and cheapest way to work out exactly what is wrong? Any help would be much appreciated - I live in Lincoln