How to Fix Car Electrical Problems - Strange problems, poor running. Sometimes difficult to diagnose car electrical problems are due to dirty or corroded grounds or the pins on the connections for the engine management system or any of the sensors. All the parts may be good and it will be a real mystery why a car has intermittent problems with poor idle, poor performance, hard starting only sometimes, stalling or occasional misfire at times or runs perfect at other times. You don't want to just visually check the pins on the engine wiring connections, but you want to also physically clean them with a fine wire brush and then spray them with electromotive cleaner. After you clean the connections thoroughly, physically plug in all the connections several times to make sure they are making good electrical contact..