any ideas why all of a sudden (directly after, like within a day of my aformentioned battery issues, and a long trip, where i added a "high mileage injector cleaner" to the tank) i've got a rough idle. really it goes through the rpm range kinda rough, but will sorta smooth out at highway speeds. idle is around 800 rpm according to the tach. i've noticed a "rich" smell a little too when i get out if i'm downwind of the exhaust... by rich though, i don't necessarily mean a gas smell, like in older cars and trucks when they load up or are running rich, but more of just a.....weird, smell. also, i noticed yesterday while waiting in a drive-through, my oil pressure guage was low...until i gave it gas to move of course, then it came on up. i know this is wordy, and probably too vaigue, but the long and short of it is, my truck's running weird, and it happened basically over night. i got in it the other day, and it had a weird vibration at idle, and i'm not sure where to start....now that you've finished my first novel...any ideas?

i'll also add that i've changed the fuel filter, plugs, plug wires and distributor cap less than 10k miles ago.

Sounds like a vacuum leak to me. A cat, mouse, or some other critter could have crawled under the hood and nibbled on something.

Thanks. i thought something like that too. after a few frustrating attempts at a diagnosis, i figured it out. i hate to say it, but a blade had broken off the radiator fan and had it out of balance. when my battery died the last time i used a jump box to jump it off (in the rain) and, at start, the box fell foreward off the manifold and the fan was hitting the edge of it. i didn't think much of it at the time, with the rain and the fact it didn't seem like it was really hitting much...but i assume at that point it had broken a blade and i didn't realize it. so, problem solved. new fan, no problems. thanks for the suggestion though, that would've been the call in any other situation i'm sure.