So i just rebuilt the motor in my truck(90 burban with 350) Its totally stock exept its bored .020 over, and has a diffrent(still very computer freindly). Now i have a code 33. According to this sighthttp://chevythunder.com/fuel%20injection%20troubleshooting%20pg%20a.htm#32 It means that the map is bad. I replaced it, and still no diffrence. Does anyone know if a valve staying open(as in being too tight) can cause this? I put a vacume gauge on it and it reads about 20in of vacume which tells me it dosnt have a vacume leak. The needle on the guage dosnt stay exactly in one spot but its pretty close. The symptoms: Basicly only at idle, it will kinda run like it has a really big cam in it. smells like its running rich, then while driving it just dosnt quite feel like it has the off the line pep that it ought to. Though i have only got on it about 35% throttle sence the motor is so new. I dont know anyone have any ideas?