98 SC2 P171-Fuel trim System Lean, help fix Please!
 

Hi,

My pristine & stock automatic 1998 Saturn 1.9 DOHC SC2, 130K miles now has
Only DTC
P171(Fuel trim System Lean) and it seems to crank a bit more than it should before starting.

When I clear the code with a scanner, I get the code again within a few days of driving.
-
Before this, I replaced the Front O2 sensor with a Denso w/oem connector because I was getting codes
P171(Fuel trim System Lean).
AND
P131(O2S circuit low voltage sensor 1)
P137(Fuel trim system lean)
P1133(O2S Insufficient switching sensor 1).

-

I've read that P171 can be caused by any vacuum leak, commonly at the intake manifold gasket-needing replacement.

But I haven't found any obvious hose leak.
With the engine idling, I did spray starter fluid on vacuum hoses and around the intake area. But no change in idle was noticed.

I suppose the next logical thing I need to do is replace the intake manifold gasket and then clear the P171 and see if it comes back.

My scanner did not have a freeze frame accompanying the P171.
But I did take some screen shots of live data at idle, after I came home from driving around, shown below.

I am still new at interpreting scanner data into something investigative.

Any suggestions?

Thank-you
https://cimg3.ibsrv.net/gimg/www.sat...cdfd1843cf.png
https://cimg5.ibsrv.net/gimg/www.sat...1f46c577c5.png
https://cimg9.ibsrv.net/gimg/www.sat...964e02fb8a.png
https://cimg0.ibsrv.net/gimg/www.sat...075764fb3b.png
https://cimg1.ibsrv.net/gimg/www.sat...511acb1ad1.png
https://cimg2.ibsrv.net/gimg/www.sat...fdd72a1d86.png
https://cimg3.ibsrv.net/gimg/www.sat...c8b81e3d4a.png