1994 Dodge Intrepid won't run unless gas pedal is held down

Engine Performance problem
1994 Dodge Intrepid 6 cyl Front Wheel Drive 150000 miles

I replaced the intake manifold gasket on a 94 intrepid 3.5L and now it will not start unless I hold down the gas pedal. If I let off the pedal the engine dies. It doesn't run well at all when I am holding down the pedal.

There isn't any black smoke coming from the tailpipe so I don't think it's flooding.
I listened for vaccum leaks holding a large hose to my ear.
Each plug seems to be firing because the idle drops when unplugged.


any thoughts on what might be causing the problem.