This might be a long shot but it would appear the 1.8's injectors tend to get mighty dirty over the years. My 318 ran with a little bit of a miss and a bad coolant leak (conection at back of head) when I got it. I pulled the intake to replace the connector and was shocked at the state the injectors were in. I cleaned them with carb cleaner and compressed air before I put it back together and low and behold the mix was gone. I've seen photo's of other peoples 318's injectors and they looked pretty gunked up as well. Before you pay for O2 sensors you may want to find a good scan tool - one that will give sensor data and not just codes. I have a snap on one. This will tell you what the O2 sensor is reading. It will also tell you what all the other sensors are reading including the MAF. The codes are only part of the pic. Example, you have a bad spark plug, ecu says misfire, due to the plug, the o2 sensor say to much fuel in exhaust and give a code, knock sensor may retard the spark trying to fix the misfire and get out of range. you get the point. | 
Linear Mode
