Ok to begin here a few months back I had a bad fuel pump and it went unnoticed for too long and it caused damage to all 8 injectors and they had to be replaced also. My fuel pressure was back to normal (my mechanic told me I don't have a gauge), and my truck had alot of power so I didn't really worry any more about it. Well I got a few misfires a few weeks back so I went out and bought a Scangauge II to moniter my FICM voltage which is relatively normal (47-48v). I keep hearing from these fourms that I have the classic symptoms of a failing FICM and the scangauge readings for the voltage may be inaccurate. Well the misfires went away and my engine started sounding alot better. That is until I filled my tank yesterday. It drove and ran perfect until this morning and I started it up and white smoke started out the exhaust, it misfires quite a bit, my rpms were higher than they normally were, and my gas mileage decreased quite a bit. I mean I re- entered info on my scangauge bc I put a 25 gallon tank instead of a 29 gallon like it was maybe that explains the gas mileage thing bit I really don't understand. Is my fuel bad? I called the gas station and they said it was a mixture and not pure diesel fuel. If it is bad fuel what should I do? And if I do anything I would have to wait a week to take it anywhere because I leave town tomorrow.