QuestionI have smelled gas in my 96 tahoe for about 3 weeks. the service engine light came on and the code said to change the O2 sensor behind the cat. convetor. It was off for a few days and came back on. I smell gas strong while driving and worse while parked with engine running. I just want to know if there is another step I should consider cefore dropping eighty more bucks on another sensor? The oil changes are kept current.
AnswerHello Whitney,
Correct me if I am wrong, but I believe the code probably told you the oxygen sensor was reading rich.
If you have some kind of tool that told you to replace it, I haven't seen it.
A rich oxygen sensor reading is what I would expect from a perfectly good, properly operating oxygen sensor if there was a lot of unburned fuel being dumped into the exhaust system.
The problem isn't the sensor....it is the fuel.
Some reasons for unburned fuel in the exhaust are:
Need of a tuneup, meaning not enough spark to ignite the fuel mix.
Dirty or leaking fuel injectors.
Fuel pressure regulator diaphragm cracked allowing raw gas to be sucked into the intake manifold.
Vacuum leak causing the ecm to add excess fuel to compensate for the lean reading.(Doubt that one here).
Bad throttle position sensor.
If you have CPFI, which is central point fuel injection, the top half of the intake plenun needs to be removed to check it, but there is one central injector, and then plastic tubes to the six poppet valves. One of the lines could be broken, or came loose.
Extended driving with that much fuel being dumped into the exhaust system will cause the converter to overheat and melt internally, plugging it. Expensive to replace. Don't wait too long to get it fixed.
Van
