Estimate on Smoke test of emissions system? & w OBD# P1457 is it necessary?

What is your question?

My 2003 Honda Civic has pristine maintenance Record. Because it has over 200000 I got timing and water pump through dealership- barely noticeable rough sputters idle when first started - barely noticed unless paying attention... otherwise only symptom is engine light. No notice in mileage although a small difference on rpm gauge after having replaced gas cap. I purchased the car almost year ago and average 500 miles a month if that... iv gotten 1 oil change and new Cooper tires.

What makes this problem better or worse?

Nothing

How long has your 2003 Honda Civic had this problem?

Since light came on