CEL on? If so, it may show 'random misfire' on OBDII reader I got this before I replaced a
coil pack. As has been noted, check plug wires and coils, plugs if needed.
If you let a misfire go too long, it'll take out the cat (s) with unburned fuel; I know from very
expensive experience. I knew it had to be a coil, but I stupidly let it go for a week, because
it would clear itself while running, then return.
Coils are around USD27/ea. at AutoZone. Just as good as OEM. Plug wires around USD50/set,
same source. dealer cost around USD320 for wires/coil packs.