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.
I just came across a study performed by AAA regarding vehicle escape tools, and the information is certainly worth sharing:
Many people have purchased tools that can be used to shatter a window, allowing escape from the vehicle in the event of fire or submersion. What may not be known is that a growing number of newer vehicles are equipped with laminated safety glass, rather than tempered glass, on the front/side and possibly rear windows. Laminated glass stays together when broken, like a sticky spider web, rather than crumbling into small pieces like tempered glass, rendering these tools ineffective in creating an escape path! Laminated glass is used because it provides additional protection from passenger ejection and foreign objects penetrating the vehicle. Windshields have been constructed like this for many decades. In most cases one or more windows, typically a rear, is still tempered, allowing a tool-initiated escape. Close inspection of the small print on each window indicates the construction type.
Vehicle owners should identify their window type and formulate an escape plan in advance of an incident. AAA's research also showed the spring loaded tools worked better than the hammer type, particularly if one was submerged in water. They also recommend forgoing tools with unnecessary additional features.
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at email@example.com; he cannot make personal replies.
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