Computer replacement?

Hi,

I have a 99 Miata with a check engine light on. It failed emissions inspection with the following messages:

O2 Sensor Circuit No Activity Detected Bank 1 Sensor 2

Exhaust Gas Recirculation A Flow Excessive Detected

My mechanic thought he could fix the problem by replacing some part related to the O2 sensor (not sure what the part was). After he replaced it he said the problem was not fixed and now says that the whole computer system needs to be replaced ($800-1000). Does this sound reasonable to you? Why wouldn't there be more error messages or signs of a problem? Should I look for a second opinion? The car seems to be running fine except for the check engine light.

Thanks so much for your advice.

Beth

Absolutely get a 2nd opinion. Without additional information about what diagnostics the mechanic did, I cannot offer any more advice. There are tests you can do to see if the O2 sensor is working properly. O2 sensors periodically do need to be replaced. I'm not sure what would be causing the EGR issue. Diagnosing a faulty computer usually is a last resort when all other diagnostics say the individual components are working properly.

Anthony

NO NO NO don't listen to that idiot. It is really common for the vacuum ports to be clogged with carbon. you will need to remove the throttle body and clean out the intake manifold pay particular attention to the little holes where the vacuum tube hook up. the repair should be fairly cheap.

f4tc0w is right. I had the same problem.After cleaning out my intake manifold and vacuum lines it ran it ran like a top. the next time the engine light comes on don't panic. Any little thing can trigger the light.