Transamman02

I have an 02 ws6 (42k) and recently it has been given me some headaches. I have an intermittent problem. Sometimes the cars starts absolutely perfect..now that same day, couple hours later or the next day the car chugs but will not idle. I have to give it gas to idle it and as soon as i release my foot it dies? The ONLY thing that i have done differently since this has started is i deprogrammed my car with the hypertech in order to sell it. While it was programmed however I had the car dynotuned and didnt deprogram the car prior to this because I was never told to (or I'm a smuck)..either way..just wondering if anybody has had a similar situation (or has any insight)...thanks