350 FLOODING AFTER ENGINE SWAP

SWAPPED MY 350 IN MY 90 SUBURBAN FOR A YEAR SPECIFIC MOTOR, SO EVERYTHING WENT GREAT. 3 DAYS LATER MY TRUCK STARTS IDLING HIGH AND FLOODS ITSELF OUT. DID THE USUAL TUNE UP STUFF, CAP ,ROTOR, PLUGS. fUEL PUMP WAS LOUD CHANGED THAT WITH SENDING UNIT. STILL NO LUCK. BUDDY SUGGESTED FUEL PRESSURE REGULATER, SO I REPLACED THAT. REPLACED EVERY OTHER SENSOR TO THROTTLE BODY. STILL BLOWS BLACK SMOKE AND MISSES ON A FEW CYLINDER. WILL NOT IDLE ON ITS OWN UNLESS I UNPLUG ONE INJECTOR, WHAT ELSE COULD MAKE IT CALL FOR THAT MUCH FUEL? FRUSTRATED AS HELL AND APPRECIATE ANY HELP, THANKS.  

Sounds like you might have an injector int he throttle body that's stuck wide open, that'll cause the engine to flood out. Swap out the injectors, double check to make sure the fuel pressure regulator is installed correctly (the TBI regulators can be difficult to get right sometimes) and see what happens, you've pretty much eliminated everything else.

Also, change your oil! If it's dumping that much fuel the oil's been thinned out with gas and won't protect for crap.  

do you have any trouble codes when you jump the a and b connector under the dash...

loose grounds... will do what you have....   engine to battery.. engine to body... engine to ECM.. yes the ones on the back of the block or up behind the thermostat...  remember.. the ecm is only grounded to the motor via the ring terminals

the coolant temp sensor or pigtail can also cause this...   they in many cases come together... sensor and new connector pigtail...

the tbi gasket kit is usually under 15 bucks at the parts store... you might take it apart and reseal it...     examining everything for broken pieces of fuel orings....    be sure to use some light lube on the orings ...  fuel line seals can be had in fuel rail seal kits...  

the idling high tends to indicate the the coolant temp sensor has failed..

if the coolant temp does not raise above 125 quickly... and above 195 in a few minutes..  it will back the IAC motor out to try to warm the motor...       idle air counts need to be between 20 and 50 with the coolant temp over 190...    see why a scan tool is needed...  

Could be a bad oxygen sensor too.

Also, you said it idles when you unplug one injector. Does it matter which injector?