Hi,

I have a 2006 Audi A4 2.0 litre turbo with about 130 miles on it, it recently started 'stumbling' intermittently meaning while driving it seems like it mis-fires sporatically for a moment. I've taken it to 2 different mechanics that specialize in german cars and they can't figure out the problem, one even has some special audi software that he is certified in. It doesn't give any codes, one mechanic said it's the quality of gas that I'm using and I should alternate types of gas stations. Another says to add a fuel additive to it on every fill up. I'd like to keep it but it isn't reassuring to drive long distance, any suggestions would be appreciated. 

Best Regards,

Mike