My Blazer will not go over 20 Mph, is the trans bad? on 2000 Chevrolet Blazer

will not go over 20 mph

Asked by for the 2000 Chevrolet Blazer
2 answers
possibly...or clogged cat....or ignition issue...
Need more specific details is it trying to shift or does it just rev up the engine and stay in first gear? Is there a really thick floormat under the gas pedal preventing you from pressing the throttle down?