1998 Chevy Monte Carlo REPAIR

I JUST INSTALLED NEW HEAD GASKETS ON MY 3.1 ENGINE ,ALL OF THE OTHER GASKETS THAT GO WITH THIS REPAIR WERE REPLACED ALSO. SINCE DOING THIS I CANNOT NOT GET THE THING TO RUN CORRECTLY .THE CHECK ENGINE LIGHT STAYS ON ALL THE TIME WHEN IT IS SITTING THERE IDLING IT RUNS GREAT REVS NICELY BUT WHEN YOU TRY TO DRIVE IT IT HAS A SLIGHT MISS AND THE CHECK ENGINE LIGHT FLASHES OFF AND ON. I HAVE REPLACED THE MAP SENSOR AND THE COOLANT TEMPRATURE SENSOR . NOTHING THAT I DO SEEMS TO CHANGE ANYTHING .HE3LP