Probably low fuel pressure. The stuff you dad put in it was probably starting fluid down the intake. Starting fluid will always get it running if you've got spark.
Check your fuel pressure, can you hear the fuel pump running? Fuel delivery problems are common on 4.3's, so you may just be the most recent in a long line.
Let us know what you find. Remember Mark Twain said he had no respect for a man who had only one way to spell a word.
see ya
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