Sputtering while driving *update*
Reply #28 –
For anyone who was following this thread, I think I found my problem.
I was changing the fuel pump today, and I left a fair amout of gas left in the tank. I didn't have anything to siphon the gas out, so there was about 1/4 of a tank. I was trying to get the straps off, and one of the supports that the bolt goes into was completely shot.(HAYLP!)

Yeah, that's the gas that came out of it. There's a nice layer of good gas, but the picture says it all. My car runs nice in park, so while in park, the fuel pump is able to suck up all the good gas at the top. My driveway is really bumpy, so as I go down the road, it mixes all of the gas up and the engine decides it doesn't like brown gas. This also explains why it fights to get up hills, it's fighting both elevation and bad gas. I'm gonna try to get as much good gas and use that for the lawn mower...
Fuel pump will be here tomorrow along with new straps. What can I do about the broken strap support though?