Are you sure its bogging down because of too much fuel? Too little fuel will do the same thing. The first thing that came to my mind was that your throttle position sensor(TPS) might be sticking. The TPS is one of the most important sensors when it comes to fuel management and if it is sticking and thinks you are at low throttle, it will only send minimal fuel thus making your car bog down. Anything else I can think of would probably make your car run worse at idle and then run better as you increase RPMs, but here they are: bad air flow sensor, oxygen sensor, or spark distribution(plugs, wires, distribution unit, or any combo of those)