Sap, bugs and bird excrement are deadly to a paint job! The key is removing them asap, never letting them "bake" onto the car.
(I know that you didn't need this lecture, but some people just don't understand that the longer you let these sit on the paint, the more permanent damage they can do - usually by eating through the clear coat - which canNOT be undone.
)
Have you tried Turtle Wax bug and tar remover? It's really strong (even smells like turpentine). You may have to let it set a little while before wiping.
Important: Don't SCRUB anymore than you have to with any product you try. That can lead to hairline scratches in the clearcoat, which also can't be corrected.
You may just have to take it to a place that does professional detailing, but make sure it's a reputable place that won't use a high speed buffer and damage your paint job even more.
I know I didn't give you anything concrete, but DH and I have a couple of show cars, so we're pretty experienced with this...
Good luck.
