Do you have a distributor on it, or is it electronic. If it's a distributor, check the cap. If the points on it are worn or corroded, that may be it. My dad had the same problem on his Honda, the HC's failed. He gave it a tune-up, replaced the spark plug wires and replaced the distributor cap, and it passed. If it's the electronic ignition, it may be faulty. I'm no expert, but I think if the spark is bad or not a full spark, then it doesn't completely combust. That may be why you're getting high CO, CO2 and even O2 numbers. Hope this helps.
- posted
20 years ago