So my truck threw me a po174 code, lean bank two. I found a hole in the pcv elbow, so I replaced. No more rough idle. Well i erased the code and the cel came back on. po171 and 174. I have zero problems with the motor. It operates great. i double checked and no leakes. The only thing Im getting is a loud ping wich sounds like its coming from my cats ( as its heating up and then when it cools down).The code reader shows I have a closed fuel system and all o2 sensors are working. Im stumped Please help

 

check my thread man, discussion is going on there now with my truck too

 

Those two codes are most likely from a minor vacuum leak on or near the intake plenum, especially if that plenum is made from plastic. Had to replace a gasket on my high mileage '98, and it cleared the codes. Those codes come when the computer cannot adjust the air/fuel mixture correctly. They occur more frequently on high mileage vehicles and, as said, the ones with plastic intake plenums. Hope it helps.

 

I had a leaky vac hose behind the engine. Fixed it, no more codes. Also, the crankcase vent to the intake tube would do it too.

 

Ping is more than likely the contracting and expanding of the metal in your exhaust system.

 

well I found a hole in the pcv hose elbow and replaced it. I cleared the codes are they stay away, but I still get the annoying ping and I think its coming from the exaust. It wasnt there before this problem so now Im confused. Its a really loud ping, could this mean the end to one of my cats?

 

Bump. Im lost.