Q: My 2006 Buick Allure runs great except for one thing. When I accelerate, particularly going uphill, it will sputter off and on, like a hiccup or trying to clear its throat. No stalls or losing power. My husband says to ignore it, but I'd like a second opinion!
_ Betty W.
A: This symptom warrants further investigation! Whenever an engine runs incorrectly, it's likely exhaust emissions will rise, fuel economy will fall, and there can be a slight chance of damage to either the engine or catalytic converter. A cylinder misfire, for example, dramatically increases hydrocarbon emissions and reduces power/efficiency; if severe, it can turn the inside of your expensive catalytic converter into a volcano! Cylinder wall lubrication may also be washed away by a continuous misfire, shortening engine life.
A surge/stumble could be caused by erroneous sensor signals, leading to an incorrect air/fuel mixture and/or incorrect ignition timing. This could also result in engine damage. I recall a friend whose son bought a used vehicle from an unscrupulous seller. The check engine light had been disabled, masking an issue (faulty mass airflow sensor) that led to major engine damage due to abnormal combustion (detonation).
Have you noticed the Service Engine Soon (Check Engine) light illuminating? Most faults should be identified by the engine management system, and in addition to the light a diagnostic trouble code will be set (very helpful for diagnosis). The key to getting a problem like this resolved is to be able to demonstrate the symptom to the technician, ideally during a joint road test. A cell phone video (taken by passenger) showing speed, conditions and instrument readings, with sounds and narration, could also be of great value.
I hope I didn't alarm you excessively; my concerns about damage are slight. It's just a shame when trouble can be avoided and isn't.
