My spark plugs look crazy fouled on my S3. There is certainly a very strong smell of gas while it’s running and light white smoke coming out of the back. I have the 1 wire O2 sensor but no idea if it’s wired correctly or working property although it looks fairly new. Because all of the I was doubting that it’s a head gasket issue, but I could be wrong. Other ideas or testing procedures to troubleshoot? Thanks!