Using PIR 3.3 V 0.33 mA to drive 12V 4A valve coil
"Normal" mosfets wont work in this application. What you are looking for is a so called "Logic Level" fet. The devices you have likely tried have a typical gate-source voltage of 8 or so volts to get them to fully turn on. Logic level fets are far less common and and you will likely have to order one from an online supplier. IPP60R385CPXK from Mouser would work as its Vgs is only 3v.