2011 A4 sline 2.0T revs up and down idle
 

My car started revving up and down at idle yesterday after I put 94 octane at Petro Can. The engine light came but it only does it when the engine is warmed up.

The 94 octane is the only thing I can think of as the cause. Still waiting the get a proper read from my ECU but everything is closed this week end.

Could it be bad gas? Any thoughts anyone?


Thanks