Ive got a 95 chevy k1500 305 5 spd its throttle body inject it really weal lacking power and running a lil rich I have replaced coolant sensor did tune up with plugs cap rotor wires filter.and ruel filter jusy got it timed today it was 3 degrees off has.lil more power haven checked mpg wat could this be no misses stock tires and wheels does have 230000 miles.on it but uses no oil or coolant

 

I pulled codes and it had code 42 is that becaise they unhooked the wire to set timing it was 3 degrees off before set