car in question:
1990 civic with b16
walbro 255 intank pump(second aftermarket pump other failed after 3-4 months)
stock fuel system other than that
no codes


ok first my car runs ok when warmed up and a full tank for a few miles, but if i drive it for a while 25+miles or the fuel tank is half empty the car with stutter and bog.

like i posted above i had this problem with the stock pump and the first aftermarket pump i put in it would run good but when it got below half a tank i would full it up and it would take 6 gallons so it's like my tank is spilt in half.

new parts
brand new in box distributor one year ago
new wires 2 months
new plugs two days
new o2 sensor 1 year(this maybe it to)
main relay re soldered 6 months ago looks good still.

my idea's: tell me if any of these would cause this
1:bad fuel pressure regulator it's stock

2:bad wiring shorting out the pump the wiring intank is good. i thought it might be this after the first one died so soon but when i pulled it it was tight.

c3:logged fuel tank

4:would a bad fuel pump relay or bad fuel sending unit(gas gague level in tank)