The dealership checked and said everything is firing ok in the engine. But, the first 10 minutes are sluggish in the morning. Someone suggested that the Quattro needs the highest octane level of gas, could this be the problem? (I'm using the cheapest grade)
Audi Q&AAsk Your Question
2005 Audi A4 Quattro Question: Engine sluggish in morning - need octane upgrade?
matte November 11, 2009, 17:37Master
Audi certainly recommends using at least 91 octane gasoline in their engines, as they are high performance. You car, however, will operate perfectly on 87 octane and what you would most likely experience is some horsepower loss.
RepairPal has some additional information on the trade-offs: http://repairpal.com/regular-gas-is-it-ok-to-use-in-your-car
The best thing to do is to switch to 91 octane and test whether you experience a difference.
Replymatte, November 22, 2009, 18:25Master
some guy is right to recommend a fuel system cleaner. I'd just add that 87 octane isn't necessarily cheap gas--87 octane from Chevron or Shell will have all of the detergents and optimal blends, same as the 91 octane from the same pump. But cheaper gas from off-brand stations can definitely cause exactly what he says.
Answer #2some guy November 22, 2009, 15:56Journeyman
cheap gas usually does not contain much detergent and may have too much ethanol. both can cause power loss due to mixture and deposit problems. do not use dry gas (more ethanol) but do use some type of fuel system cleaner (techron or the stuff audi sells).