I'm having a problem with poor acceleration?

Yes, try a new fuel filter. Also try running two large bottles of techron fuel system cleaner through. Chevron makes this cleaner and it works best. Check or replace the air filter also. Always start with the small things first--like you are doing. Do not change the plugs until there are due, however take them out and check the gap on them. Make sure the gap isn't too big. Anything bigger than.040 should be adjusted. When you do decide to replace these plugs DO NOT use another type of plug other than A/C Delco. If you change the wires use A/C Delco also. I know these parts are more expensive, but from my experience they are the best to use in these high voltage ignition systems.

A K&N air filter will definitely cause the problem you have. In your question you said you run a washable oil filter. I assume now that you mean it's an air filter that requires oil like a K&N. Get rid of this air filter. Your MAF sensor must be cleaned also, as a result of running such an air filter. Carefully take the MAF sensor out and gently spray some CRC electrical contact cleaner or some brake cleaner on it. Be careful, this sensor it sensitive. Do this first and see if this cures the problem. K&N air filters should only be used in engines that do not have a MAF sensor. The oil gets on them and they cause all kinds of problems. To check your TPS sensor you need a voltage tester. With the key on--engine off--back probe the blue wire with the positive lead and connect the negative lead to a good engine ground. Slowly open the throttle body to wide open and observe the voltage. It should go from around.04 volts closed- to around 4 volts at wide open. It should do this smoothly. If not change it. Keep me posted.

Yes, K&N oil can get onto the MAF sensor which will cause a misreading.