I have a b2600 I started the truck to warm it up when i came back in 10 min it was idleing very rough. I tapped the gas and it died and wont start. I get a spark and there is fuel getting into the cylinder, i tested the cylinder pressure,they are all at 150psi. Any ideas what is wrong. Last moth i replaced the coil, power unit, plugs,cap,rotor and wires because i had the same problem but no spark.