91 Blazer with a bone stock TBI 350: I've replaced the knock sensor and computer temp sender before I really thought about what's going on... It runs like [darn] when it's warm, and that's about 3 minutes of driving after start up... No power below 2500 RPM, lugging etc. Motor really hesitates when you get on the throttle, like in 4th gear up a hill I'll have to drop down to 3rd and wind the motor out... I haven't even checked the O2 sensor, but that may be the problem. All I know is it's running really rich after it warms up (the tail pipe is full of really dark soot) It's not throwing any check engine light codes but it's getting to be a real pain in my butt. If I had a carb, it'd be running perfect right now. Since it's TBI, I have no idea how to tune this engine. All I know is, I can climb hills and lean to angles my previous 496 would starve for fuel at and that's a step in the right direction~ Please lend me your advice and experiences with this matter, Chad.