I have a problem here...A few weeks ago I put a fuel injector spacer on the Blazer, which was parked for a few weeks while waiting on and installing the tranny. I got it all back together finally and got her driving. Wasnt running very well and started throwing check engine light. It was a code 45 rich condition at O2 sensor. I replaced the O2 sensor and reset the ECM and drove around for a bit. Started getting the same code so I bought a TBI gasket set to replace the spacer and when I removed the TB it had a whitish brown residue on the back. It was new and on there fairly thick. It smelled like fuel and something else. Suspecting sugar (dont know who or why) I tasted it...it was kinda sweet. Put everything back together after a good cleaning and fired it up. It runs, sut has a slight knocking sound now, and the exhaust smells remarkably like brown sugar and it smokes. While it was sitting I have installed new headed gaskets, spark plugs, and Hypertech ignition and tranny. I had a really bad exhaust leak before the header gaskets and the muffler shop just installed the exhaust (again). The sound seems to be coming from the engine, more the rear, so I dont think its a leak. What can I do to be sure its sugar and what are the odds that my motor is screwed? I heard Mythbusters did this test on a sbc and didnt really have an effect. Can/should I just drain the tank and replace the fuel filter or is it too late?