1- yes i have the correct PCM
2- gas tank has no issue , gauge is reading correct
3- i checked when engine running, i opened the cap of the valve on fuel rail, pressed the vale, very less pressure and engine about to die, then get idle when relased
4-fuel filter replacement is due, but i drove this car last night to another city 30km far, i didnt have this issue till i stop at the 3rd trafic signal in that city. i returned back after 3hrs and it worked smooth till i reached. i doubt anything related to heat / engine copartment temperature? what it could be? if fuel filter is the issue, it must have given me truble whole the way.
5- i hear the fuel pump noise every time i turn the key
in my car i see the fuel rail doesnt have a return line. as i remember the filter itself is having a return line. so where can be the regulator located? or am i missing something?
If i want to check supply voltage and relay drive voltage from PCM
, how to access the terminals? i am thinking to pull the relay and insert think insulated wire to bring it out and put the relay in place so that i can check it when the issue come, is it the correct practice?
Edit: i opened the gas cap last night to see if any different , in both cases the issue remains the same.
OK, good trouble shooting feedback, too bad the gas cap test didn't prove positive, as its an easy fix!!!!. Your answer in #3 above, about the engine idle recovering when you pressed the fuel rail Schrader valve to check fuel pressure, is a good clue.
A few things come to mind that could be causing this.
1) As it seems to happen after a long drive, or in traffic, I suggest again, fuel line vapor lock, from the fuel boiling after a drive in the hot weather your having now in Saudi Arabia. If the problem began right after you filled up with fuel from an off brand, or out of the way fuel station, that was selling sub-standard fuel that didn't have its vapor pressure properly formulated for the temperatures your having this time of year. If you have Chevron/Texaco/Caltex, Shell, or BP gasoline available, maybe try one of them & see if things improve.
2) An aged, weak, failing fuel pump, or pressure regulator assembly, that's likely located in the fuel tank, is having intermittent problems building & holding fuel pressure. Could be a grain of sand that's gotten past the in tank fuel pump "sock" pre-flter and lodged in the pressure regulator, or drain-back valve holding it open so that the pump can't build proper fuel pressure. So perform a proper fuel pressure test, with a gauge connected to the fuel rail Schrader valve test port (where you bled the fuel pressure off in your trouble shoot) & post your fuel pressure Numbers with the engine cold and at idle & at say 2500 rpm
, then do it again when the engine is warm & about to stall. EDIT: Also leave the fuel pressure gauge attached to the fuel rail after you turn the engine off, then time & post how long it'll hold fuel pressure & what the fuel pressure number is.
3) A line, or gasket, or seal problem, in the fuel tank, with the fuel pump/pressure regulator assembly, intermittently picking up air & injecting it into the fuel line, or with shifting debris clogging the in tank fuel pump pick up sock pre-filter, so the pump has problems sucking up enough fuel to build pressure.
4) As has been suggested, maybe intermittent low operating voltage to the fuel pump. As has been said, the in trunk fuel pump inertia cutoff switch electrical connector is an easy access test point, to back probe the fuel pump electrical B+ feed, as it'll test most of the electrical wiring to the fuel pump for under load voltage drop.
More thoughts for consideration, keep us posted on your trouble shoot.