Here in Portland, OR, cars must pass an emissions test done under load on a dynanometer. My car, after replacing plugs, air filter, and changing the oil, came up high in hydrocarbons. It was within limits on NOx - the mechanic I called suggested this implied that the catalytic converter is functioning properly - and barely within limits on CO.

Anyhow, as this car has taken its share of abuse in its 180K miles, I am not in a hurry to dump another $1K (I'll explain momentarily) into a car valued at less than that by, say, half. Two years ago, in order to pass the emissions test, I had to pay for the removal and replacement of the O2 sensor (it was fused onto the exhaust manifold and required hours of service to be drilled out, two shops concurred with this diagnosis) and the leaded fuel fill pipe restrictor (requiring the removal of the gas tank, this may not have been required, but neither mechanic could determine this with certainty).

I feel that the motor is probably in decent shape, though at 180K a soon to be performed compression test would confirm this.

The mechanic told me that the O2 sensor currently installed is "sluggish", but I hesitate to replace it if in fact it is the air mass meter that is to blame. Obviously, I can't expect a "satisfaction guaranteed" answer to my question, but

1) is it likely that the O2 sensor would go bad in 2 years time?

2) is there a way that I can reduce the cost of replacement of the air mass meter from the quoted $550 by doing it myself?

In both cases, it would be nice if I could further diagnose the problem and any parts acquired from junkers, etc., before investing any more money.

Thanks for your help,

Victor Weinstein