Chevrolet Repair: 90 gmc 5.7L T.B.I. runs real rough, fuel pressure regulator, plug gap

Question
My 2wd sierra 1500 just turned 100K I bought the truck at 93K at 98K it smelled super rich and ran like it sputtered!? I did complete tune up(plugs,wire,dist. cap,rotor,O2,MAP,TPS and took apart and cleaned the T.B. w/a toothbrush and replaced all gaskets and fuel pressure regulator)Plugs looked so badly carboned on some you couldn't even see the electrode!Running rich and sputtering again it pours blue smoke when you hammer it.It's only been about 3000 thousand miles since major tune up was done. Any ideas WTF it could be? current mileage is 100,246. Thanks

Answer
Hi Jason.... did you see if it was generating any codes....look down the TBI when running it should have a nice fine spray like a cone... if not check the inj. try a good inj cleaner.or replace it...also check plug gap. the blus smoke could be a stuck open PCV allowing engine to suck oil.when you replaced the plugs were they the same heat range...hope this helps