DeVille Engine Misfiring During Acceleration, Fix Guide

As a CTS 2002 owner, I faced nearly identical symptoms last season. The check engine light came on, accompanied by rough running and combustion misfire during acceleration. The throttle response was notably poor, especially when trying to pass on highways. The root cause was a faulty fuel injector. These symptoms typically indicate fuel delivery issues, either the fuel injector itself or related components in the fuel system. In my case, carbon buildup had clogged the injector, preventing proper fuel atomization. The repair involved: Diagnostic testing to confirm injector failure, Removing and cleaning all fuel injectors, Replacing the defective injector, Performing a fuel system cleaning This was a serious issue requiring immediate attention, as faulty injectors can lead to catalytic converter damage if left unchecked. The repair took about 4 hours at the shop. While fuel injector issues are common at this mileage, having a professional diagnosis is crucial since similar symptoms could also point to fuel pump problems or ignition system faults. I would recommend getting it checked soon, as driving with a bad injector can cause additional engine damage and worse fuel economy.

Thanks for sharing your CTS experience, the symptoms sound exactly like what my DeVille is going through. I plan to get it checked this week based on your advice about the fuel injector system. Just curious, do you remember roughly what you paid for the full repair? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up? The check engine light has been worrying me and I want to make sure I address everything while its at the shop.

Great to hear back. After taking my CTS to the mechanic, they found and fixed a defective injection valve that was causing the combustion misfires. The total repair came to 515€, which included the diagnostic work, parts, and labor. Since the repair, the engine has been running perfectly with no engine misfiring or throttle response issues. The check engine light cleared up immediately and hasn't returned. The sluggish acceleration problems completely disappeared, and the car feels like new again. The mechanic mentioned that catching these injection problems early helped prevent any additional engine damage. Regular fuel system maintenance is now part of my service routine to avoid similar issues in the future. If your symptoms match what I experienced, you're likely looking at a similar repair cost and outcome. The peace of mind from having it properly fixed is worth the investment.

I took my DeVille to the shop yesterday after getting your helpful advice. The mechanic confirmed it was indeed a fuel injector problem causing the rough idle and engine misfiring. They found two clogged injectors that needed replacement, which explained the severe power loss I was experiencing. The total bill came to 680€ for: Diagnostic testing, 2 new fuel injectors, Full fuel system cleaning, Labor costs While it was more than I hoped to spend, the difference in how the car runs now is incredible. The engine feels smooth again, no more hesitation during acceleration, and the check engine light is finally off. The spark plugs also showed some wear, so I had those replaced while they were working on it. Really appreciate the guidance, you helped me avoid getting overcharged and gave me the confidence to get it fixed before causing more damage. The car runs like new again and I learned an important lesson about regular fuel system maintenance.