I have a 99 mercury cougar with a obd emission code of P1151, can someone tell me what this code is?

I dont know the code definitions off hand, but I do know that if you take it to an auto parts store, they will usually test it for free. I take mine to auto zone. The only problem with their readers is that they will only tell you what is being affected by the problem, and not whats causing the problem, but its free, and it will point you in the right direction.