Expert: Sean Halliday - 6/10/2006

Question
Hello Sean, I just purchased a 2000 Audi A4 1.8t,auto transmision,56k. My first Audi, car starts right up, cold/hot doesn't matter. Idles OK when in park. Now, drive down the road stop at a red light , car idles erratically-tack bouces up and down a little, when you try to pull out car hesitates and jerks some. I have been told(by non-mechanics)that maybe the dealer put in low octane gas, I have also been told this is Audi(Nature of the Beast). I need an experts opinion, that is why I am e-mailing you Sean, Thanks for your help. Tom

Answer
nope,,not your gas,,,and its not a audi fault cos ive driven them and its not a comman "fault",these cars dont do this unless they gotta problem which i think could be the fuel filter or EGR valve,,,,you need to get it checked out by a reliable audi tech,,,,sometimes it is a vacuum fault or idle air control problem but its not your gas cos they run fine on 87 octane .is your check engine light on?....without seein the car and running some tests its hard to say ,could be a few things,,MAP sensor,MAF sensor,air temp control,,bad plugs,misfire,,,,,,wires,,,,,,,,,,,,,,,bad electrics,,,,,,,,,just get a good diagnosis from a trusted mechanic.he should find the fault,,