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.
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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).

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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