what is a new o2 sensor...new fuel filter...and pcv valve going to do for my car? just got the fuel and pcv installed on 6-29....thanks

With the number of miles you have, it'* only a guess - could range from dubkus to a radical difference, but these items normally address a 'failing' condition (miss, hesitation, fuel mileage, stalling, etc.) Most of the time, a new fuel filter will do nothing at all assuming you are doing it as preventive maint. instead of trying to fix a problem with fuel pressure or fuel starvation. If your filter is just 'normally' dirty, it will still allow enough fuel flow volume to provide the FI pump enough volume of fuel to keep pressurized and enough fuel to volume at high RPM. Many times, at WOT a dirty fuel filter will flow well enough to run the engine up to a certain RPM (well, assuming max pulse length under high load) and then hits a plateau where it can't give any more fuel so it starts flaking out. This is kind of rare if you use good fuel, and replace it regulary. If it'* never ever been replaced, or the old had a blockage, you may see better upperband response.

The PCV valve is an odd bird. Basically, it'* a one-way checkvalve. It'* job is to use vacuum from the intake to pull out fumes from the crankcase. As the fuel detonates, some of the gases in the cylinders pass by the rings and pressurizes the inside of the engine. This valve opens (kind of like a weight on a pressure coker) and vac. sucks crap gas out of the crankcase. Over time, it gets mucked up with oil. If the valve gets sticky, it can make the engine idle roughly.

The O2 sensor is probably the thing that has the most potential to affect performance. The data from it makes the ECM to make real time decisions on fuel mixture. There is a good web page I saw about O2S'* I'll try to find for you. Their appearance can tell you a lot about your engine. I'll see if I can find it.