So I bought this cheap, in good condition with blown head gasket. Replaced head gasket, had head seviced at local shop. Ran ok, but rough, underpowered. Let sit a couple of months, would not start. Fuel pump relay good, fuel pump getting power and fuel guage not working. Replaced fuel pump, will idle ok with occasional miss but when put in any gear other than p or n, it idle drops to 300rpm or so and stutters and tries to stall. Smells like it is rich, and plugs show slight fouling but not the worst I've seen by far. Any ideas? I'm a motorcycle mechanic, and after a bit cars start to baffle me.