P0171 system too lean bank 1

Cleaned mass air flow replaced fuel pressure regulator replaced fuel filter there are no vacuum leaks could it be the fuel pump?

 

Check throttle position sensor......
.....it would be nice to hook up a scanner and run live data while engine is running....

specifically the fuel trims, maf volume, temp, and throttle position.....


where does the lean occur ......at idle.....or highway........

It could be a number of things....or several things at once.....

Injector condition comes to mind.....

 

On the highway the long term FT is 30 plus short term stays around 0

 

What year and engine?

 

The test procedure in this post helped me diagnose my issue a while back. Happy to try to talk through any of it, though I am far from an expert. Good luck!

 

Makes me suspicious about your egr......
if it was stuck open you'd be getting too much air......

 

2001 toyota tacoma prerunner 2wd v6 and is there anyway of testing egr ?