when they said AFM tampered with, did they mean you re-soldering the joins or something else?? i guess you stopped them making more money outta ya for fixing that for you.. $4000 for major service is alot, there are guys who have done 100K service for around $1000 as per threads.. sorry to hear about ur experience.. i have nismo afms otherwise would have lent that to see if problem clears up.. before spending any more money, maybe find someone here that can lend you their AFM to test on your car and go from there.. its a quick simple job.. pity u selling ur car bcoz of it