Alfa 147 rough idling
I've recently begun to experience misfiring/rough idling on my 2.0 TS Alfa 147 (2006, 140, 000km). The car will run smoothly during the first few minutes on a cold start but will develop symptoms after a short period of time when it starts to warm up. Moderate vibrations can be felt when the car is stationary, seen whilst inspecting the engine and misfiring heard through the exhaust. Additionally, black smoke is also blown out of the exhaust during hard acceleration although this happened on occasion prior to the idling issue.
There doesn't seem to be any changes in performance during normal driving except for the fuel consumption which seems to have increased (currently around 14L/100km). Things which I've tried so far include changing the spark plugs as the old ones were fouled, replacing a damaged ignition coil, cleaning the MAF sensor and resetting the ECU. Looking at getting advice from you guys for other likely remedies.
Any help is appreciated. Cheers!
Last edited by gchui; 04-01-15 at 11:28.