Quoted from Kawydud:
I couldn't get a good look at where your shooter tip is compared to the ball at rest. For some reason the Stern shooter rods are a bit shorter than most. I have replaced most of my shooter rods on my Stern games to get the tip of the plunger touching the ball at rest. If it isn't touching, the shooter rod has to go past its resting point to get any force on the ball. Which makes it a very weak plunge. Swapping out the shooter rod with any aftermarket one makes the plunge so much simpler. If it is the auto launch mech that is giving you fits, there are a lot of threads with fixes for that.
Here is a picture of my stock Iron Man shooter rod next to the new one I bought, a bit of difference in length.
I have an aftermarket one that is longer and pushes up against the ball like you mentioned. I actually tried putting some wahers to make it shorter to sit more like a stock stern so the tip is behind the ball.
The issue happends on both auto launch and manual plunge. I am thinking its that Metal fork ramp. It doesnt look centered but I dont know whats normal. Can you take a look at yours and take a pic? I circled where I need you to focus on. the arrows that is painted on the playfield doesnt line up with the arrow on the metal fork. Is that supposed to be like that?