[eccs19]

No engine light is on. I do have a code reader, so I'll check to see if it's got anything in memory. Not sure how I would check the cat, but my mileage seems fine, and I expect if it's the cat, I would notice a mileage difference between the 2 cars.

I like the MAF idea. I'll do that next time.

As for your last suggestion (vac line), would you by chance have a picture of where this one is?

Thanks for the ideas.

Edit - Just checked, no codes stored.