Hey, sorry it's taken so long to update, I got hit with some out of this world virus that's had me in bed the past 4 days. So the vacuum lines are all in decent shape and the MAF screen looked fairly clear of debris. I pulled the front 3 plugs just to see what they looked like, they all had burn marks on the insulators and the gaps were a little wide (worn electrodes) but I didn't see anything that would indicate they weren't doing their jobs. I regapped them and put them back in, with no improvement as I expected. It definetely seems like a timing/ignition issue to me, like just one cylinder is firing intermittantly. It smooths out with higher rpms. I got some more details from my sis about how it started, she says she pulled out to pass someone and it happened while she was doing that. She heard some sort of "backfire" noise and then it began to idle rough. There are so many possibilities right now I don't even know where to begin, blown head gasket, bad valve, blown piston, bad coil pack, bad cam sensor...I guess I should do a compression test to start with. I sure wish those back 3 plugs were easier to get at...
