L27'* got the HO2 sensor. Check your emissions label. If it says "HO2" on it instead of "O2", you DON'T have the single wire.
In other words, if you're heated on the O2 filament, you don't use the same sensor as the L67 engine.
Here'* what you're looking for on the radiator core support:
This is from a 93 L27. My bet is yours is HO2S.
This is from a 93 L67. Tell us which you have, we'll tell you the right sensor part number.
Throttle Body and MAF sensor cleaning is in Techinfo, the link at the top of the page.