Hey guys I'm new to this site and here's my problem with my s4 my ecu is Apr flash and i had my engine swap out for a new one. So my question is do I have to install a stock ecu for the new engine because my mil light came on it say system to lean bank 2 and I check for vacuum leaks and sensors.

 

Anyone out there

 

No ones cares

 

if its the same engine, you shouldnt have to put in a stock ecu. if you're really worried about it, take it back to whoever flashed it and see if they'll flash it back to stock and then put the tune back on. they should have your stock tune on file. also, just because your sensors look good or don't seem like they're messing up, doesn't mean they can't be. try logging your data and comparing to nominal results you can find online. or use vagcom for a full scan to see if it will tell you what exactly is the problem. system too lean can be a number of things

 

Thanks for the information,but i did get a scan and i got p0174 and p0171 system to lean bank 2.but this could of bein from the old engine problem due to no compression so I cleared all the old codes and um running the car to see if the mil comes back on