Here's my situation. Tell me what you think. I was in my SPF MKI (injected) a short distance from home when I was hit by a massive thunderstorm. Driving along I first noticed some backfiring on the over-run when shifting. Then, after a short stop to wait for traffic, the engine began missing. Things got progressively worse as I limped home, and the engine finally stalled in front of my garage. I let things cool down and dry out for a few hours and tried to re-start. Things were obviously not right, and I think I had a back-fire through one of the injector stacks, so I just put her away and called the engine builder (Roush). While awaiting their reply I've been trying to figure out what might have happened. My take is this:
The O2 sensor is mounted at the junction of the "bundle of snakes" right below the ventilation opening in the rear deck of the MKI. I'm betting the icey cold thunderstorm deluge was running down the back of the car and dumping down directly onto the O2 sensor which in turn started enriching the fuel mixture (causing backfires). Then, while stopped for traffic, the situation worsened and the plugs began to foul when I pulled away. As I limped home the whole system probably fouled out, perhaps even trashing the O2 sensor, to the point where the ECU doesn't know what is going on at all, and nothing works. I'm interested in other opinions and tactics. First change spark plugs and try again? Can I test the O2 sensor somehow?
The O2 sensor is mounted at the junction of the "bundle of snakes" right below the ventilation opening in the rear deck of the MKI. I'm betting the icey cold thunderstorm deluge was running down the back of the car and dumping down directly onto the O2 sensor which in turn started enriching the fuel mixture (causing backfires). Then, while stopped for traffic, the situation worsened and the plugs began to foul when I pulled away. As I limped home the whole system probably fouled out, perhaps even trashing the O2 sensor, to the point where the ECU doesn't know what is going on at all, and nothing works. I'm interested in other opinions and tactics. First change spark plugs and try again? Can I test the O2 sensor somehow?