Hi, I've been having some troubles with my car. When I give to much trottle the rpm drops or the engine stutters. First I tought it was my tps or cas but now I have installed a fuelpressuregauge and when I give it some thottle is stays at 39psi, but from the moment that I turn the engine off, it just goes immediatly to 0psi.

I have put in a new SARD fuel pump and fuelfilter, so what do you think is wrong?
I don't hear the pulsation damper clicking anymore? Is my FPR gone?

 

The fuel in the rail is supposed to be trapped b/t a check valve in the STOCK fuel pump and the FPR. The FPR is obviously there. The check valve seems to be non existent in your new pump.

TRAPPED, as in when the key is to off, the fuel should remain trapped in the rail, then very slowly depressurize. Like thirty minutes to depressurize. Or more.

 

Will put the old one back in and see if it holds pressure, but since I had this problem with the stock pump I am really thinking that the FRP is malfunctioning.
Is it normal that the pulsation damper isn't clicking anymore and that the pressure stays the same at idle or wot?

 

Same pressure at idle and wide open throttle is a wrong condition.

There is a vacuum hose that goes to the stock FPR. It regulates the FPR.

At idle supposedly you should see about 28psi. I never see less than about 31psi on any of my cars. At full throttle with a non turbo, you should see approx 39psi give or take. That's because of the Lack of vacuum at wide open throttle.

If you have a non turbo, all one has to do is idle the engine or if you want turn the key just to ON and jumper the fuel pump check connector. Then get a piece of spare vacuum hose and put it on the FPR. Watch your fuel pressure gauge reading as you first suck on that hose then blow into that hose. The pressure gauge should respond. Going down when suckinga and going up when blowing into the vacuum hose. I use a MittyVac and apply 10psi with it at the FPR. The fuel pressure, even on a non turbo will rise to approx 50psi at ten psi.

I'd do the above with the engine off and key to ON with the fuel pump check connector jumpered.