ok i can start the car right up, drive it around and all that (38-40psi fuel presure) but then i can shut it off.Restart it and the car bogs low rpms , So i see the fuel pressure its around 30-20 psi normaly its 38-40. anyone have a idea what could cause it. I just installed a new fuel pump not it. Figured the pump was gettin heated up.

 

Can't quite understand what you're saying.

 

when i start the car up the fuel pressur is around 38-40. seems after i shut it off then restart it it only goes to 30-20 psi the lowest in fuel pressure.

 

Sounds like a sticking injector when it gets hot. (Happens in common rail diesels unsure about these injectors.)

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How are you measuring the fuel pressure do you have an aftermarket Adjustable fuel pressure regulator?

 

yes aeromotive fuel pressure gauge.

 

check the voltage at the pump when the pressure is low, if the voltage is above 10v and it's still low then check the fuel filter, if the filter is unobstructed then you probably either have a bad fuel pump or another issue with the fuel system(cracked hose or kinked line).

 

Where your tank vent line goes into your charcoal canister, open the opening up in the canister with a drill bit. Just clear it out, no need to take the nipple off. I think I used something like a 1/8" bit.

I had similar issue, this fixed it.

 

took that out .. changed fuel pump and fuel filter .. same issue

 

check the voltage when the problem occurs, as mentioned. it could be a bad ground or other wiring issue. heat increases resistance and vise versa

 

voltage is 13.5 or so when its losing fuel pressure.

 

were you measuring across both the power and ground pins at the pump? or just placing the + lead at the power pin and - lead at chassis ground?