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 ..........like 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?