My son has a 2000 Ram with a 360 Magnum, he just replaced the plenum gasket and now the truck smokes so bad you can't even see it when it is running the idle surges and will die most of the time and will only run about 40 mph hour down the road. anyone have any idea what might be wrong, truck didn't smoke until he replaced the gasket

 

what color smoke? Could have not seated or sealed the gaskets at the cylinder head to intake manifold correctly.

 

+1... Something was installed wrong. And was cat checked and o2's replaced?

 

my guess is its prob lettin coolant by the gaskets and thats ur smoke problem. it would be white smoke. as far as the dieing prob and wont idle that could be the o2 sensor, the precat one, or the IAC itself, but id guess its the o2 causing it and its prob because you have so much coolant going into the chamber its making it die like that. fix that prob and i bet it all goes away.

 

smoke is blue, cat is good and new o2 sensors, and I too feel the intake is not either seated correctly or gaskets got wrinkled when they put it together. Truck never smoked like this before. We are going to take the intake back off our selves this time and check it. I will let you know what we find

 

Make sure your coolant reservoir has no oil in it and your crankcase has no coolant in it.