Hello, I had an exhaust manifold stud rust away on my 97 4.6L on the passenger side. I had bought one of those clamp-a-stud things to fix it, hadn't gotten a chance. Started truck Saturday, loud as usual, also got Check Engine code P0171.. I finally installed the clamp to fix the exhaust leak, and reset the Check Engine light. Could the Bank 1 lean error be caused by the exhaust leak? I am hoping so, I am due for state inspection...

 

You said you reset the CEL. Did it come back? - Yes p0171 can be caused by an exhaust leak but can also be caused by other things such as; dirty maf, stuck pcv, bad o2 sensor or a vacuum leak.

 

Has not come back yet, I've driven 3 times since (only a few miles each time).. I am hopeful it won't...

 

If you cleared the codes, you are going to have to drive it for a while before inspection so all sensors achieve readiness status. If you have a capable scanner, check it before you go to make sure there isn't a P1000 in there. If there is, DO NOT try to clear anything or it will just start the cycle over again.

 

Thanks, I have a scan tool that I can use to verify all the monitors are in Ready status.