Ok I started noticing this issue about 2 yrs ago on my 92 Camero Z-28, I have a High pitch howling sound coming from my Fuel Tank area. It seems to start when the car would get up to operating temperature on a very hot or warm day ,but besides the howling noise and the occasional fuel smell in the car the car would run and perform well. Now being that I have a little more time on my hands the other day I decide it was finally time to have the problem taken care of. After having the car looked at in the local auto shop the mechanic told me it was theFuel Pump. In the process of changing out the fuel pump he found a crack around the lower portion of the fuel tank fuller neck, so we change the fuel tank out also.

After picking up the car the car ran good for about a day or two before it started Howling again, so immediately I brought the car back to the shop. The minute I pulled up at the shop the car died and as we were trying to get the car started again it started sounding like it was out of gas. I had to leave the car again and for about a week the mechanic couldn’t find out why the car would not stay running then he decided that it was the fuel pump sending unit, so we change that out only to be right back with the same noise except instead of having a steady tone of high pitch howling the howling sound is up and down now and when this happens the car speed tends to go up and down also in unison with the howling sound like a fuel line or vacuum line is collapsing on itself, but the mechanic told me that my fuel lines and Vacuum lines are good, so can you Guys help me out AKA Can’t Get Right and I really don’t know if everything I’m being told is right either. Thanks Guys

 

I had the same howling but i only have it when im low on gas, I ran a couple tanks of fuel injector cleaner through it and it seemed to help. (it was also fuel system cleaner) But i read somewhere else on here that it could be a clogged fuel return line, so just for fun blow some compressed air through the lines, disconnect them on both the engine and tank first of course. hopefully this helps