2000 GT reduced power lately.

Lately my car just doesn't have the usual response or "pull" when giving it full throttle , I also notice a slightly rough idle along with random "bucking" sensations at lower speeds, I was wondering what are some common areas to look at with these symptoms.. its worth noting Ive owned the car for a little over a year and haven't done any kind of tune ups on it yet (other than change oil & filter every 3,000. changed air filter and recently had trans & rear end fluid changed).

I'm starting to wonder if one of my cylinders is down (fouled plug / bad cop etc.) is it possible to pull wires while the motor is running to check for a missing cylinder?

The car has 70k miles and is all stock except for centerforce df clutch.

On my previous 73 Camaro I would pull plug wires until the engine idle remained the same to pinpoint a fouled plug. wasn't sure if i could do this(safely)with the way these modular motors are setup.

Thanks!

Thanks for the tips im going to replace the fuel filter first and go from there, is it ok to buy an Autozone branded filter?

I changed the fuel filter yesterday (I hope autozone brand was OK, that's all they had) and seem to notice a slight improvement but not what I hoped for, the old fuel filter dropped out a bunch of nasty looking sludge when I disconnected it.

Next up ill try replacing the spark plugs, any specific brand I should get?

I also read you can test each COP with a multimeter, I have a multi but not sure whats the normal range of numbers I'm looking for?

Thanks!