03 mazda Tribute v6 I had one of my Catyliconverters replace and still haveing problems with it not accelerateing over 10 mph and wanted to see if I could just takr off the rear exhaust manifold and see if that changes anything will my tribute still start

 

If it can't go faster than 10 mph it is most likely in limp mode and you should have a veritable x-mas tree of warning lights and trouble codes. And it probabaly has nothing to do with the catalytic converter. A transmission problem is more likely.
Does the engine rev up when in N or P?
What are the trouble codes?

 

no it idles a little ruff but not bad and when i hit the gas it revs up a little and goes about ten miles an hour and if i let off the gas it dies and there is no error codes at all

 

Agent:

But why do you think it is a cat problem?
What did you do to diagnose it?
What did you do to eliminate other causes of rough idling and lack of power?