sounding more like a head gasket.... A compression test might help. Check the oil and antifreeze for signs of contamination.

Have you checked the codes yet? Replacing plugs and wires is probably a good idea if they were very old, but don't just replace parts.

Our coil packs are very reliable, so the odds of all of them failing is very slim. And if you did the spark test I described, you'd know if the coils were working or not.

If you are near littleton I could help you take a look.

I guess you didn't do that did you?

LOL... probably would have just showed the P0300 we already know about anyways.

Could be others as well.

I've never been a fan at throwing parts at a problem when the troubleshooting isn't finished.

Only as a last resort will I condone throwing parts at a problem.