So I have a 96 audi a4 2.8 fwd its a 5-speed. The car feels like it is mis-firing but its not turning the check engine light on. The car runs fine no issues but when sitting at a light for a long time or sitting in a drive through it will just shut off, starts right back up no issue. What could be causing this? It has a 139,500 on it, Im thinking a tune-up might help or Idle air control valve? Has anyone had this issue? Also a side not, my speedo and rpm gauge don't work, speedo just bounces on the 0mph and the rpm just sits a 0rpm. Please help!!!!

 

Well as far as the idle issue, it could be plugs or coil-pack

 

Start w/ a set of plugs, since they are cheap and readily obtainable. Use the OEM NGKs, which I found online for just over $4 each.