My 2000 Chevrolet S10 ZR2,

My 2000 Chevrolet S10 ZR2, 147,000mile is miss firing and hesitating. Comes up with codes P0301, #1 cyclinder misfire and p0453. I took my truck to Chevy garage and they did a compression test, came back ok(120psi)in all cylinders. Had cyclinder leak down test proformed, 100% leak. I took the heads off when i did #1 push rod had some carbon build up. Had them sent to a machine shop, they were pressure tested and decked. They said heads were fine. I have replaced, Distributer and module,Distributer cap, Rotor button, Plugs & wires, Fuel injector assemlby/spider, fuel filter, air filter, egr valve, map sensor, airpump check valve, most vacume hoses,gaskets from the head up, and checked the timing chain. Do you have any idea's about what my problem is? Thanks