So I have a 98 GT 4.6 with the codes misfire cylinder 4, P0401 exhaust gas recirculation flow insufficient, p1401 differential pressure feedback egr circuit high input.

When my car is stone cold it takes me cycling the key two three times and about three to five revolutions for it to start but it drives no problem. Once it starts warming up I have a constant misfire(which I think is causing the misfire on cylinder 4 code) but when it is at operating temperature it runs great besides slight bogging down sometimes if I gun it too hard.

i just replaced my intake manifold, rebuild fuel injectors, replaced all vacuum lines besides the molded EGR lines, the differential pressure sensor, the Vacuum likes to that sensor, the EGR valve and cleaned the throttle body of all carbon before putting back together.

I couldn't get the idle air sensor on the throttle body off so I just soaked the whole throttle body in carb cleaner to help break up the carbon.

What am I missing that could be causing this problem?