Hey everyone. First time poster. I've been looking through some of the threads and have found them very informative. Here's my deal. I have a '99 Miata with 40000 that has been running Mobil 1 10w-30 for 38000 of those. I have noticed for the last couple of changes that I've been down about a quart. Since the last change about 1500 miles ago, I was down about 1/2 quart. I change oil religiously at 3000 miles. I've heard conflicting things from different people regarding syntheitc vs. dino oil consumption. The Mazda mechanic went so far as to say that in the case of the Miata engine anyway (4 cyl, 1.8, redline at 7K RPM), synthetic should not be used and that I should be using dino oil only. My questions are: Is there any relation between using synthetic and seeing the consumption of 1 quart in 3000 miles? Would dino fare any better? 1 quart in 3000 miles seems a bit excessive in a car with 40000 miles on it. For what it's worth: No leaks/seepage found anywhere, tailpipes stay reasonably clean, no smoke from the tailpipes (except a white vapor when car has sat for 30 minutes or so which goes away after driving). Also, plugs are completely clean, and the oil looks normal. I'd appreciate your feedback. Thanks!