Toyota Solara intermittent rough running and power surging issue despite changes to plugs, wires, and PCV valve on Toyota Solara

Some Toyota Solara owners report experiencing intermittent rough running and power surging issues, even after changing the spark plugs, wires, and PCV valve. These problems may be attributed to a vacuum leak, which is a common cause of rough idle and can significantly affect engine performance. Additionally, faulty ignition coils are reported to cause misfiring, leading to similar symptoms. Even with new spark plugs, improper installation or defects can still result in rough running. In some cases, engine backfiring has been noted to contribute to these issues, potentially linked to the fuel or ignition systems. To effectively address these concerns, owners are advised to conduct a thorough inspection of the vacuum system, ignition components, and fuel system, and to consult a mechanic or Toyota dealership for a comprehensive diagnosis and repair.