help with rail switch

In my 2008 model 308 diesel vehicle, the reel switch needed to be changed, but the masters can't be sure, I don't want to give that money for about 400 liras for the spare part, I don't want to give that money in vain, the reil switch in the broken car suddenly stops at high speed, it works again, it doesn't stop at low speed, the error code in the brain says it's the relay switch

It is necessary not to say and pass the rail switch. It failed 2 times. The first fault was: air flow meter failure, low pressure failure, etc. in the fault codes. Trial and error revealed that the switch was faulty. After 2 months, the switch failed again. When I tried the part on another vehicle, there was no problem. .I rode it for 2 months with a malfunction. As a result, it broke the pump at the end. I can say it was 15 when the cost was 3, a rough draft. The 400-lira piece cost me 4 thousand. If the fuel pressure sensor is faulty, it cannot measure the fuel pressure momentarily. It cannot understand the instantaneous value. As soon as it cannot read the instantaneous value, it adjusts according to the idle value. That is, it causes a lean mixture, and it causes a rich mixture at low speed.