I think I need a CPI, can this cause my 94 Blazer not to start competely? (I have gas in my oil)

you have either a leaking CPI, or leaking fuel supply lines in the intake (commonly called a nut kit). remove the upper intake and inspect. washing on the drivers side is the supply line, washing on the passenger side is the CPI leaking.

in either case, if you have more than 70,000 miles on it, replace both as 100,000 miles seems to be average replacement time anyway unless your lucky like me. my 95 S-10 CPI has 177,000 miles on the original CPI unit.

the CPI unit runs $250-$280 or so at Advanced, Autozone, etc. the nut kit is a dealer only item, and i think its $40-50 or so.

obviously you'll want to change your oil and filter afterwards.

On the passenger side, it was clean, the drivers was not. I did change the oil and filter, and it started right up for about 20 seconds and then in stalled, now it wont start, but everything turns when I turn the key. I know that if I change the oil and filter, it will probably start up again for a little while. When I try to start it, I smell gas. I just want to make sure that this is most likely the reason causing it not to start, before I put money into it. I think this mught be the original CPI for my truck? It has 170,000 miles on it. Is the CPI something I can do myself?