Indeed, there is no CPI in a 98. The Gasoline smell could be bought on by a missfire, dumping raw fuel down the exhaust. I am with BlazerLT on this one, do your basic, complete tune-up, all new air and fuel filters - stick to OEM GM AC/Delco parts for your wires, cap rotor and plugs, and see what happens.
Do it soon too - it probably will not be too much longer before the catalyst and/or an O2 sensor shows problems from the heavy fuel enrichment.