Some tree sap is almost impossible to dissolve with most detailing products.
As a solution that has worked every time I have tried it get some turpentine. Always test it on a hidden area to be absolutely sure that it will not harm your particular paint formula.
I soak (pretty wet but not dripping) a clean terry cloth towel with turpentine and lay it on the sappy area. Let it melt the sap, then turn the towel over and let the other side loosen it even more. Blot the sap residue up, don't rub since the sap probably has grit embedded in it. Once you have the sap dissolved get another clean towel and wet it with turpentine and gently wipe the area to get the last of it off. You will have to throughly wash the area after you have all the sap removed. I use Optimum Power Clean. Then it will be necessary to polish the paint finish to remove any damage that the sap and the wiping with the terry towel did to it. You could use an inexpensive MF towel too. Just remember to throw it out afterwards, since the sap residue will harden on the towel and it will scratch the hell out of anything you use it on.. Be sure to let all the turpentine evaporate before throwing the towel in the trash. There is a slight chance of spontaneous combustion.