That's like asking, "How many licks does it take to get to the tootsie roll center of a tootsie pop?"

It can be many, many things. It's hard to diagnose. A bad map sensor can be the culprit, but then I think you'd get a check engine light.

What octane you running? A D16 only needs regular unleaded. Unless you're forced induction/high compression, high octane is a waste. I read that it may affect gas mileage but you can't believe all you read. I rhyme :chuckles: