1.) Check for leaks, clean all the nostrils right past the throttle body. There should be 4. 2 for the crankcase ventilation that runs through the pit of **** below the injector rails and 2 the for IAC.
2.) Also you could turn the intake manifold over and remove the two large hex bolts to clean part of the EGR. That area is when exhaust fumes run along the bottom of the intake to the EGR.
3.) Most importantly check all of the couplings. Those things can leak like crazy if cracked. I just made my own new couplings with 2" length pieces of heater hose cut by hand. Works like a charm.
4.) I recommend replacing all of the vacumm hoses too...If they are old and dried out.
As a temporary fix for the intake to head gaskets you can remove, clean and then spray black spray paint to them which helps with a better seal.
