I am struggling with an issue for some time. My car idles a little bit rough. No error code is thrown. This is especially noticeable if car is well warm up. I have already replaced O2 sensor 1 and cam sensor - I've got error codes indicating those 2 (not at the same time) and also I failed inspection due to emissions. After replacing those 2 parts errors went away and after replacing O2 emissions are now perfect. However, the rough idle remains, again no error codes this time. Recently I checked my MAF readings at idle. It fluctuates between 3.2 g/s and 3.6 g/s. Shouldn't be this value closer to like 2.3-2.6 g/s? Does it look like MAF sensor need replacement?
Also O2 sensors readings are strange. As far as I know O2 sensor before cat. readings should constantly fluctuate between 0 and 1V and readings for second sensor should be more or less constant. However, this is not the case here, especially at idle. O2 sensor 1 readings sometimes fluctuate but for several seconds can stay at the same level or change very little. For O2 sensor 2 the readings behave somewhat similar to O2 1 but fluctuates to lesser extent. Again, no error code is thrown. I'm guessing this might be related to bad MAF as well
Also O2 sensors readings are strange. As far as I know O2 sensor before cat. readings should constantly fluctuate between 0 and 1V and readings for second sensor should be more or less constant. However, this is not the case here, especially at idle. O2 sensor 1 readings sometimes fluctuate but for several seconds can stay at the same level or change very little. For O2 sensor 2 the readings behave somewhat similar to O2 1 but fluctuates to lesser extent. Again, no error code is thrown. I'm guessing this might be related to bad MAF as well
