Hey guys, just joined and was wondering if anyone could point me to a thread about my problem. Got a 93 Silverado with a 350, 5 speed manual in it. K&N filter and a Flowmaster on it, Last year the mileage went way downhill and failed emmision inspections because of H.C.s. Put new plugs, wires, cap and rotor on and it barely passed. Only getting around 8 MPG now where it used to get close to 14. Changed distributor a few years ago and also egr valve. Anyone got any idea why it's running so rich?

 

Welcome to the forum...
If I recall the 93's used TBI or throttle body injection, have the injectors ever been serviced ? they do wear over time and they could be leaking, and or have a poor spray pattern...