Okay, here's the scoop. I've got an 88 Volvo 740 that refuses to pass the local environmental gas tests. From the start it originally read lean, then switched to rich once I replaced the o2 and thermosat (cooler). Very frustrating!

But that's not the question, that's the problem. The question has to do with constantly being charged to test the results. Getting expensive as its been in for 5 tests without success. So, I'm looking for a cheap testing kit for NOx and CO. Ideally something that can be attached to a VOM or laptop. There must be somebody that manufactures these things at a reasonable price suitable for a shadetree mechanic. I'm dreading the results of testing the 95E320 (is coming up next year). I would love to be ahead of the crowd.

So..does anybody out there know of some solutions?