These 93 to 95 4.3 liter engines are common for leaking gas, causing the right side of the intake to be clean due to leaking gas. There are 2 options for a leak which can be replace the spider assembly(recommended) CarQuest part# FJ226R, which is a Standard brand componet. The other option if its just the regulator leaking HELP, and Standard make a repair kit for these. The HELP part# is 55162, and the Standard part# is PR484. After changing this, make sure that you change you oil, because it's sure to has raw gas in it. Hopefully it hasn't destroyed the bearings with gas in the oil. Check the oil to see if it's overfull. Vapor lock is not common at all on fuel injected vehicles, and the engine would have to be warm for this to happen. You can disconnect the battery, and crank the engine over by hand to see if its seized up.