My 87 K5 is running rich and I am running out of options, please help. I have set the timing, adjusted the idle in accordance with the procedure on thirdgen.com, changed O2 sensor. It still smells really rich and exhaust tips are black. cant run with my back window down cause of the smell. Any other suggestions? and what is normal oil pressure PSI, i put a new gauge on and cruising pressure is about 45-50psi. Is this high, low, or just right? Thanks in advance!