I ordered (2) bottles of autorx for our 1992 Buick Skylark (122,000 miles), I decided to start out with clean oil (havoline 10W-30) rather than just adding the autorx to the existing oil. When I opened the autorx bottle I was suprised that it looked so dark, almost like chocolate syrup, and it seemed kind of thick too. I'm hoping to maybe get 2 or 3 more MPG after two treatments, has anybody achieved this? The car has had very frequent oil changes since we've had it, but the first 80,000 are a mystery alas the autorx.