I have both CRC electronic cleaner and Deoxit...haven't seen much difference in performance between the two products over the past couple years. I think CRC and a toothbrush is the way to go for most cleaning needs. Make sure the plug seals and boots are good and if they are not, replace them, or you will be in the same boat again. I had an old Ferrari and I replaced all the pins, seals and boots on every Bosch connector on the engine harness....took me about five nights after work to complete. Half the boots were torn and connectors green and tarnished. Had to cut back the wires up to an inch to get to clean wire (corrosion was under the insulation) It was very satisfying once complete and the car ran great after and idled much smoother.