my 1988 bonneville LE has a fuel pump whine and stalls, only does it when warm though. After that it wont start immeadeatly, but after about 20 minutes it works again. thought it might be something wrong with the fuel delivery system but talked with my dad he says it might be a vapor lock or some problem with vacuum lines. If anyone has an idea anything is welcome.

Thanks in advance!

Check the fuel pressure. The fuel pump my be starting to die.

Agreed. Vapor lock pretty much went away with tank mounted pumps and fuel injection. We are talking, at minimum, 40+ PSI in the fuel lines.

Yep, vapor lock went away with submerged fuel pumps.

Yeah i did check the fuel pressure and it was high but i didnt know how much higher it Was. I will check the actual pressure tomorrow. Also this is actually the 4th fuel pump i had in it in the last 2 to 3 years. I think something might be destroying it though.

Changed many pumps on customers cars over the years. Main reason for pump failure: running car low on fuel or running out of fuel.
The gas actually keeps the pump cool, so when low pump will heat up.
This comes from Spectra Premium and Delphi.

Yeah the first time it failed it had run out of gas. But ever since then i have kept it at at least half of more .

make sure you got a new filter and no kinks in the line too

You may have some restriction in the fuel lines.

Thankyou guys you have helped narrow down the problem, now i actually have somewhere to start. Ill check my filter again and the flue lines for kinks.