Pontiac Other

I have 132,000 miles on the car. So the check engine light is on, I got the read out and it says low effincency catalidic I take it to the muffler man he checks it out with a infa-red heat sensor on the catlyst and says its not that. Did he check it right. My car engine hesitates on occasion. Could it be an o2 sensor? AlsoI feel like get as much horse power as I should any suggestions? Should I have the fuel injectors cleaned at a shop? This whole thing basically has to do with the check engine light and it saying low effincency catalst so if its not that could it be an o2 sensor? Any replies would be greatly appriciate thanks
April 18, 2007.

Was that a po420 code?

Could still be the converter, just because it isn't super heating doesn't mean it's working.

Really is there a way to test the cat to know for sure >? Could it be an o2 sensor >? I dont remember the exact code though if it was a p420 code what does it mean? Are there diffrent numbers for low effiency catalyst that would mean something else? Thanks for your reply

Apr 18, 2007.
You need to find out what codes are in there. Before you can troubleshoot po420, (which it sounds like your describing), there are about 20 codes that CAN NOT be present, before troubleshooting this code.

IF that is the only code, than you need to check for an exhaust leak at the O2 sensors or any up to the engine. Excess oxygen throws out the true readings of the gases by the O2 sensors.

Since you say that " sometimes" you have the power you expect it to have may mean the converterter is broken intrnally and intermitantly plugging up.

So find out the codes.

Ok I will and ill get back to you I really appriciate your response's it help a whole lot thanks and I will get back to you on the codes

Apr 19, 2007.