crankshaft sensor replaced, still showing same code, same problem

So this sounds similar to what we are experiencing with our 2003 HSF 2.4L... Several months of the car losing power, RPM's all over the board. Could restart it and be fine again for a while. Someone recommended we use SeaFoam, which we did 3x. The check engine light even went off after putting the SeaFoam in. Finally after almost a tank and 1/2 of gas it just outright died. Would not restart at all. Took it to the mechanic and the diagnostic said cylinders were not firing on #1 & #4 and that the crankshaft position sensor was bad. Replaced the timing & balance belts, and the sensor. (Mechanic ordered parts & installed them on accident, I had not agreed to the $1100 bill, that's a whole other story). But he said the bad news was the sensor he put on was bad as well. So we ended up having our friend do the work and when he put the sensor that I purchased on, the car will still not start. I'm wondering if it's just the wiring connecting the sensor?