Buick Riviera misfire during acceleration at 55 to 70 mph despite new plugs, coils, and wires on Buick Riviera

Some Buick Riviera owners report experiencing misfires during acceleration at speeds of 55 to 70 mph, even after replacing spark plugs, coils, and wires. These issues may stem from a partially clogged fuel filter or a failing fuel pump, which can lead to a lack of power during higher-speed acceleration. Additionally, improper installation or fouling of spark plugs can contribute to the problem, necessitating a double-check of their installation. Faulty ignition components, including spark plugs, ignition coils, or fuel injectors, may also play a role in the misfire. An imbalance in the air-fuel ratio is another potential cause, and adjusting this mixture may help alleviate the issue. Furthermore, while accelerator position and MAF sensors have been replaced, verifying their proper functioning is crucial to rule out any related problems. The misfire, particularly at partial throttle, suggests that the throttle position or associated components may require further inspection for optimal performance.