2013 equinox stumbles for a short period, recovers, low side pressure varies.

What is your question?

I did about 100 miles of driving on monitor of PID parameters. Noticed that when the low side pressure is regulating well at 58 to 60 psi: Never stumbles. Other times the pressure falls into the low 40's. This is when the car may stumble and misfire. When it does misfire the pressure can dip to 38 psi. If you stop and turn the car off and restart usually it starts right back up and the pressure will be higher. The high pressure side of the system is widely variable in pressure (300 to 1500 psi) and seems to have no bearing on if it stumbles or not. But the l low pressure side definitely has a correlation to the fuel pressure and stumbling. The engine is the 2.4 L Ecotec, with direct injection. Now the question: Can the low pressure side dropping to 38-42 psi cause stumbling? Should the high pressure side vary that much but dropping to 400-500 psi while idling does not seem to affect anything and when I step on the gas it is back up to 1400 psi. Suspt screen plugging low side

What makes this problem better or worse?

only happens after about 10-20 miles of driving

How long has your 2013 Chevrolet Equinox had this problem?

Months