If the catalytic converter is plugged the engine will idle unusually smoothly and you'll hear more of a hiss from the tail pipe rather than the normal "putt putt". At higher speeds there might be some popping back through the intake. An air filter would have to be really plugged to be noticeable. Remember, it has to be able to pass enough air to let the car go over 100 miles per hour. Hopefully you're only asking it to go half that fast which means about 1/3 as much air and fuel. I don't think this applies to your engine but if it still has a distributor, retarded timing can cause a severe loss of power. A real good clue, if you have the header-type exhaust manifold with thin metal tubes instead of the cast iron manifold, is it will turn orange when the timing is retarded. That's because the fuel is fired too late and finishes burning in the exhaust manifold instead of in the cylinder. Next, check for any air leaks in the fresh air tube between the mass air flow sensor and the throttle body. Also look for vacuum leaks. Any air that sneaks in that doesn't go through the mass air flow sensor won't get measured and the Engine Computer won't command the matching amount of fuel to go with it. Another plan of attack is to use a scanner to view live sensor data while you're driving. Also look at the fuel trim numbers. If they are very high positive or negative, the computer is adding or subtracting a large amount of fuel from the calculated values in an attempt to correct a problem. That problem could be related to low power.
Tuesday, March 15th, 2011 AT 2:50 AM