I'm thinking of buying a 1990 rx7 rag top non-turbo.

I went and looked at the car here is what I found

Has 89,000 miles

-outside body is awsome, orig paint still looks amazing had it on hoist un carrige is A1 condition.

-interior is a write off
-needs a new convertible top
-missing headrests

I'm more concerned about how it ran.

-Cold idle it ran like a bag of ****. He said it was normal I dissagree I know they wouldn't let a car leave the factory running like that. Once it was warmed up ran like a champ. I rev'd it a few time when warmed up didn't see any excess smoke. Coolant seem to be up to proper level. Oil was clean and proper level. I though I could hear a vacuum leak, but not sure all the rubber hoses and everything under the hood look MINT and very clean.

is the big thing that conserns me .. should i be worried and what could I check?

I am very mechanically inclined just know nothing about rotory engines