I was wondering if a worn out cat can cause my cars performance to decrease ? It feels as if the car runs a little out of air at about 3500 rpms. It just won't pull hard from there on anymore.
It doesn't die on me, neither does the cat glow after a long ride. It also doesn't stink like rotten eggs.
So, could a cat cause that problem ? BTW The cat is still the first one, car has 38.000K
thanks
Alex

 

From my experience, yes, a clogged cat can make your car act that way. However, since you mention not noticing any smell or glowing, I would consider a few other things before replacing the cat at 38,000 miles.
How is the overall state of tune of your engine? Have you replaced the fuel filter and air filter(s) lately? Is the ignition system up to the task? (plugs/wires) If your engine is starving for fuel or air, or can't adequately ignite the mixture, it may drop off at high RPMs.
On the other hand, how is the fuel in your part of the world? Does it contain compounds that might clog your cat more quickly? Seems like low miles for a bad cat, IMO, but I won't say it's impossible. Hope I've helped you.