I'd bet it's the fuel filter, most likely not replaced on schedule. One easy way to see if your VX has been serviced is to check the belts and hoses, they should be new afeter just being replaced at 30k. Look at the aifilters, and your fluids check bolts should at least be oily with fresh tool marks. If any of this is not true, have it maintenanced for 30k services ASAP.