i have an mk4 with a 2.0 aeg and for the last few months the coolant temp gauge hasnt been working right...it fluxuates all around from the cold position to 190 and back to cold....ocassionally it wont want to start and when it finally does it smells heavily of gas and other times ill be driving down the road and ill notice it wants to rev up and back down and act all weird on me...and if i hold the cluutch in eventually it goes away...and it always misfires when idling (when i first start it in the morning it seems worse) but that could be due to a tune or something being needed....i did go get the scanner put on my car and heres the codes and the probable cause of each
P0102: -large vacuum leak on engine
-faulty mass sensor

P0455: -faulty vent solenoid
-faulty purge control solenoid
-faulty fuel tank pressure sensor

P0411: -faulty air solenoid valve
-faulty air pump motor

P0116: -low coolant level
-faulty Engine Coolant Sensor
-poor electrical connection

P0422: -rich air/fuel ratio
-air leak near rear O2 sensor
-fauly fuel control O2 sensor

I was told before that probably my engine coolant temperature sensor on the coolant flage could be bad and it could be causing all my problems but do you think that all these could be related....the last code is probably because my resinater is gutted...but i have noticed with the air pump that the aftermarket intake was put on without a breather filter on the one hose where it was taken off...and the other day i shut my car completely off and my air pump was still running i turned it back on and shut it off and it stopped...i was just wondering what my most probable combination of things was faulty on my car before i buy all this stuff and it ends up being only the 25 dollar coolant sensor...if you guys think it could be the air pump too...where do you think i should get one?