[polygxn]

pawn Code:

pvtime[playerid] = 25;
pvtimer[playerid] = SetTimerEx("pvTimeDown", 1000, 1, "d", playerid);

This is not how you use timers. Take a look here: https://sampwiki.blast.hk/wiki/SetTimerEx

pawn Code:

SetTimerEx("pvTimeDown", 1000*25, 0, "d", playerid);

Also, read what the "note" says: https://sampwiki.blast.hk/wiki/SetVehicleParamsForPlayer