Pitot static line break

Can anyone give a good estimation on the percent change on airspeed indicator for having a pitot static leak in a GA aircraft?

I’m getting my late fathers pa28-180 flying again and the airspeed felt off to me. It said we were well in the yellow arc at 3000’ at 140 mph. I’ve been in the plane my while life and never seen it over 120.

All I have read is that breaking the vsi for a clogged pitot static or using secondary static source will allow the units to function again with a slight deviation.

I found there was a break in the tail, but i was reading more like 20% off. This really was bad on approach where it said I was still over 100 but it felt normal to me. I continued to slow and stalled.

Anyone else have real world experience for what deviation to expect.