Hi Guys I am new to the forum.I have a stock 1987 5.7 tpi iroc-z auto. last week my fuel punp has started buzzing when the engine is running also wont shift in to third when pushing her and a lack in power but is ok at low revs there is small pressure in gas tank when the cap is removed the fuel filter is new when i switch the car of the pump still buzzes for afew seconds and stops any ideas would be appreciated.

 

Welcome aboard thirdgen.org.

The pressure in the tank when you remove the cap is normal. Running for a few seconds after the ignition is turned off isn't what is intended, but isn't a big deal.

You need to get a pressure gage on the system to monitor fuel pressure while these symptoms occur to determine whether it's a fuel pump problem. It probably is, but you should verify that before changing it out.

Not shifting to third under power is probably a transmission problem (been there, had that). The bad news is you're probably looking at a transmission rebuild.

(Moving this from Carb to Tech.)