Alfa 147 Engine Performance Issues Point to Fuel System

On my Alfa 156 (2003, gasoline) I faced nearly identical symptoms last year. The rough running and jerking during acceleration turned out to be failed fuel injectors. After proper diagnosis with an OBD scanner, two of the fuel injectors were found to be clogged and not spraying fuel correctly. The lean condition triggered both poor performance and the check engine light. While the oxygen sensor can cause similar symptoms, the jerking during acceleration is a telltale sign of fuel injector problems. The throttle body and intake manifold were also inspected but were clean. This was a serious repair that required replacing both faulty injectors. The job involved removing the intake manifold to access the fuel injectors properly. A full injector cleaning service was also done on the remaining injectors to prevent future issues. The symptoms you describe match classic fuel delivery problems. Having the fuel injectors tested should be the first diagnostic step. If left unfixed, bad injectors can damage the catalytic converter due to unburned fuel.

Thanks for sharing that experience. The symptoms you described with your 156 match what I went through perfectly. My mechanic also found clogged injectors throwing off the air-fuel ratio. The mass air flow sensor was tested but was working fine. After replacing two bad fuel injectors and cleaning the others, the engine runs great now, no more rough running or check engine light. The spark plugs were also replaced as a precaution since they showed some wear. Just curious, do you remember roughly what the total repair cost was for your injector job? And has everything been running smoothly since the fix? My Alfa has been good for about 6 months now but always good to hear long-term feedback.

Great to hear your Alfa got sorted out. After my injector replacement, the engine has been running perfectly for over a year now with no check engine light or performance issues. The lean fuel mixture problem was completely resolved. The total repair came to 515 Euro for replacing the faulty fuel injectors, which included labor to remove the intake manifold for proper access. While it was not a cheap fix, the improvement in performance and fuel economy made it worthwhile. The rough running and hesitation during acceleration disappeared completely. A properly working injection system is crucial for the right air-fuel mixture. When fuel injectors fail, they can cause all sorts of driveability issues. Regular fuel system maintenance and quality fuel can help prevent injector problems in the future. Good to hear your car has been running well for 6 months. With the new injectors and spark plugs, you should be set for many more trouble-free miles.

Last week I finally got my Alfa fixed after dealing with those exact symptoms. The mechanic diagnosed clogged fuel injectors causing the lean fuel mixture, which explained the rough running and jerky acceleration perfectly. The repair involved replacing two faulty fuel injectors plus cleaning the others. While they had the intake manifold off, we also did new spark plugs since they showed wear. The whole job cost 480 Euro including parts and labor. Made a huge difference, engine runs smooth as silk now, no more check engine light, and proper power delivery. Just hit the 1000km mark since the repair with zero issues. Really glad I researched the symptoms beforehand so I knew what to expect. This mechanic did great work and the price seemed fair compared to what others paid for similar repairs. Definitely keeping an eye on the fuel system maintenance from now on. A clogged injector is no joke when it comes to engine performance and fuel economy.