I have a 1993 S-10 with the 2.8L V6. 2 years ago it failed the smog inspection. After new plugs, wires, cap, rotor, oil change, air filter, O2 sensor, and coil, it passed. Although after the BAR audited the garage, it was found that they did not test it properly (within correct RPM range).

Since the inspection (2 years), I've put another 50k miles on it. Total mileage is about 225k. I'm getting great mileage (still about 27 MPG), but you can smell that the truck is not getting a complete burn.

I plan on doing... plugs, oil change, fuel injector cleaner, and air filter before I take it to get tested, but since it probably wouldn't have passed 2 years ago had it been tested correctly, I doubt it will pass this time.

Ideas, sugestions?
a

The tune up plans along with your present outstanding fuel milage should have you in shape to pass.