lilbluetruck98

Lets start with what has been replaced
spark plugs
wires
distributor cap
rotor button
ignition coil
tps
crank sensor
distributor pick up
iac
ecu
fuel pump
fuel filter

runs fine when first started but after its driven for about 15 mins under just about any load the fuel pump pressure drops to zero then back to between 30-40 psi drops back to zero the back to 30-40 psi ect ect ect

tjwalker

Fuel pressure regulator is a suspect here....

lilbluetruck98

tested the regulator and it works fine even bypassed it and it still acted up
its like the fuel pump loses power, if the regulator was faulty the pressure wouldnt drop to zero there would still be something registering on the gauge

Firestorm500

Sounds like an electrical problem--either faulty ground, power feed, or the plug itself.

Did this happen before AND after fuel pump was replaced?

lilbluetruck98

yes it did this before and after i replaced the pump, symptom didnt change at all after i replaced it

Firestorm500

Therefore, it is not the pump. Something is getting hot and interrupting the electrical path.

tjwalker

I agree. Have you swapped the fuel pump relay with a different one yet?

lilbluetruck98

Yes i have swapped the fuel pump relay, twice actually strill does it. Im about to the point of wiring the fuel pump to a toggle switch

86jeepmj

my 89 did this. my orange wire with a black tracer that goes to the ballester had a little rub place. when it touch metal the ecu wont send fire to the pump. it took me 4 days to find the rub wire. my was right under the right head light. i changed the filter, pump, relay, i started checking the continuity in every wire is how i found it. hope it helps

lilbluetruck98

by passed the ballast resistor and still have the same issue. I guess its time to start tracing all the wiring