A 1992 with a 1.8L engine? Stock?
 

Can this be true? The mystery of the 1.8L Engine - While perusing over the engine of a Miata, my father noticed the sticker inside the hood, giving the engine specifications; it said that the car had a 1.8L engine. "Oh cool," I thought, and the seller chimes in that it is in fact the special edition car. I brush it off as a nice plus. I got home later that night and began my research. Wikipedia says that the 1989-1993 cars had 1.6L, and only in 1994 did they begin making 1.8L. (Now, I am telling you all things you already know, but this was my process of discovery.) I called the seller back the next day and mentioned this curiosity.He said that a woman had come to look at it, and almost bought it a year ago, but the seller backed out. She had the same question, but apparently she returned to purchase saying that she had found something indicating that the car was genuinely stock. I called the local Mazda dealership and asked for the most knowledgeable person there for Miatas. He seemed to think that a 92 would never have come with a 1.8L. I also checked the VIN, it was for a 1992 Miata, so it isn't an issue of him not knowing his model year. He checked that the VINs around the car all matched. Any discussion would be thoroughly enjoyed.

The hood was likely off a different car. The sticker with the displacement also has emissions year listed. Check that. Then check the VIN on the hood matches the one in the dash and the ones on both doors and trunk lid.