Stuttering in first gear, then she sings in 2nd

Hi- I emailed the guys and they said the best way to get an answer was to post here, so here goes. I have a 2013 Subaru Impreza base model 5 speed. It has 90k plus miles on it and had the clutch replaced at about 85K. Since the clutch replacement I have noticed that starting out in 1st gear there is hesitation and some times it will stall instead of having strong pick up in 1st like it used to. I tried troubleshooting and put some higher octane gas with some seafoam in there for two tank fulls to see if it was bad gas or something. The problem seems to have improved or I may have just gotten used to it. It only seems sluggish in 1st gear every so often. Doesn’t actually stall but chugs along i 1st for a little too long. Do you all have any ideas on this one? I sure could use some help.

Has the check-engine light come on at any time? If so, you should have the codes read.

Try changing the plugs to see if that makes an improvement. You are coming up to the time to replace anyway,

Thank you. The plugs have not been changed. Mike

No check engine light, but another member recommended changing the plugs which has never been done. I will try that. Mike

be sure to check the plug wires (if any) at that time, or just replace them.