Did you remove the coil stops and inspect, or just look at them installed?

2 weeks old?

I would first contact the distributor you bought it from, if they can't/won't help, then contact Stern directly.

My guess is bad coil stops... common on new Sterns.
Order some new replacements from pinball life.

I second that u need to remove the coil stops to verify that the rivited stop is still in place.

Here is the link to pinball life
https://www.pinballlife.com/flipper-coil-stop-for-sternsega.html

Is this your first game? Have you cleaned the playfield? 2 weeks of constant playing Without wiping down Or cleaning the playfield should show some difference in the play ability. However, if it’s a considerable difference, then yea, may want to look into the coil stops as some have suggested.

I'd check the EOS contacts and the flipper button contacts, then. On KISS if the EOS was making contact, but it wasn't solid, it gave you really crappy flipper power. So manually move the flipper and look at that EOS connection. Likewise make sure the flipper switch leaves haven't moved out too far and aren't making good contact anymore. Bend them in toward the cabinet if need be.

If both those check out, make sure you have a credit card's thickness of clearance on between your flipper and the flipper bushing by pulling up on the flipper vertically. It should move a little, then go down when you release. If it doesn't the shaft may have worked its way down causing the flipper to bind on the bushing, robbing it of power.

what????????? where did you come up with this nonsense?

Likely it's something simple.

And if you're desperate, you can eliminate the node 8 board as the problem by swapping Node 8 and 9 (setting the dip switches appropriately) and seeing if the problem goes away.

You're under warranty, though, so if it is the node board, you're covered, and he should be too.

But I doubt it's 2 node boards.

This. I bet your flippers are installed with no clearance. Being pulled into the coil at an angle causes friction between the plunger and sleeve and will sap power. They probably worked OK at first because everything was new, but once a little pinball dust was generated it grinds into the sleeve.

What you want is the plunger to pull into the coil perfectly straight. Sometimes a bit more than a CC worth of clearance is needed for this.

Just trying to rule out the obvious. Some people may not clean their playfield after a few hundred games and it would be a considerable difference in play. Is that ok with you? SHEESH.

Here’s another thought, simple check which may lure in other technical a-holes, but Screw it - at least I’ll offer ideas and help. But, check the gap of your flipper(s) and Make sure they’re not dragging or getting caught on the playfield. I know some people have had that issue on newer sterns. I believe the simple check is being able to place a credit card smoothly through the gap.

Not sure why your original comment provoked such a hostile response (seems to be the tenor of the times at Pinside these days, unfortunately), but you were absolutely correct to make this suggestion.

Most of the parts stores sell a flipper gap tool with their rebuild kits which is 1/32" thick. A credit card does essentially the same thing. For whatever reason, it sounds like your mechanism does not have enough space and should be an easy fix with an allen wrench. I've attached the Service Bulletin #108 that discusses this topic for the SEGA-style flipper mechanisms and all mechanisms have similiar gap requirements in this respect. Look at the middle of the second page and they specific under the note that "1/32" UP and Down movement"

Stern-Rebuilding-Flipper-Service-Bulletin.pdf

The flipper gap is a good suggestion. I've seen humidity level changes and the games level change this gap and cause flipper binding.