I'm looking for some thoughts and insight. My 97 Sahara popped up a check engine yesterday. Today i drove it to work in the morning with no problem. Looked up the code listing and checked it at lunch. It is giving me a (72) "Catalyst efficiency below required level. (Same as code 64)".
Now, I am driving home on lunch break and she starts hitching or dropping power occasionally. I let it sit for 30 min at home. Come back out and everything starts up fine. The code is still there so i take it around the block and it is pretty rough dropping out like it may stall. Then it is ok for a bit and goes to rough running again. Pulled back in drive way let it idle and it was all over the place.
ANY THOUGHTS ON WHERE TO START??
History: 200k on it. Fresh rebuilt transmission, Cleaned IAC a while back and took care of idle problem. Has 250miles on new plugs, wires, dis-cap, rotor, air filter, Crank sensor. All has been good since the tune up till now. I do have a cracked exhaust manifold and a leaking valve cover gasket, but they have been there from the beginning and never affected normal running before.
??? Cat, O2 sensors, Exhaust, Something else????
Thanks in advance.