97 tahoe 5.7

I have a 97 Tahoe 5.7 vortec. It started missing lately. I took it to a buddy of mine and he hooked it up to a coder. It said it was either a crankshaft or camshaft position sensor. It also started leaking coolant approx 3 months after this problem. Does anyone know where the crakshaft position sensor is located? Thanks,

So what was the code number, P1345?