P0304 on 1998 Silverado k1500

Question

When pulling a load up a hill the engine knocks and misses and loses power

Answer 1

Engine knock oin up a hill, check the cooling system low on coolant or water in the radiator. Check the sparkplug condition also. when the gap on the sparkplug increase the fuel system tends to lean out, proper sparkplug and its gap is essential for engine power especially at a great load such as going up hill