I have a 1996 gmc yukon 4x4 have flood problems I have put in new fuel pump has good fuel pressure changed coolant sensors changed throttle body changed computer plugs wires distributor cap and button coil etc very hard to start then floods realy bad at idle seems to clear up a little after driving couple miles down the road then when left idle to long goes back to flood and pooring out black smoke

Harvey N Tawatao

• 3854 Answers
• Posted on Jun 12, 2009

SOURCE: 1994 GMC WON'T IDLE AND FLOODS OUT

Did you check the fuel pressure and the fuel pressure regulator???. Not sure if you have the X or the W engine. The X you need 13PSI to 14.5PSI to have fuel injectors to run right, if you have the W type engine you need 60PSI to 65PSI to have the fuel injector to run right. If the fuel pressure is bad it's could be leaking through the diaphragm into the manifold. Good luck and hope this helps.

marcial adorno

• 246 Answers
• Posted on Sep 08, 2009

SOURCE: Won't start

check the IAT(intake air temperature)sensor, if its bad may cause a no start situation and flooding,also check foe fuses to the ignition system and voltage to the coils

SOURCE: 1994 Yukon running rich and flooding

Fuel pump circuit (low voltage)
Try replacing the fuel pump relay or testing it if you have the manual.

SOURCE: 1997 gmc yukon lower intake gaskets replaced now

head gasket

SOURCE: Describe your Specs timing Gmc 350 1988 Problem

18436572 firing order