Depending on model of truck , some had final chance screen behind the top mounted lpg pressure sensor and some had them located behind the fuel supply nipple on the injector holder its self. With KOEO do you hear lpg spewing? If so, it is flooding. See which oriface the spewing is coming from on the injector holder. if it is the larger hole 1200 o'clock position then you have a sticking injector. if it is the small hole at 3 o'clock position , you have a sticking relief valve in the injector holder its self. This requires new injector holder. but first be sure you check the small 5 amp fuse on the main lpg injector.