1999 Limited w/260k - P0300, P0301, P0302, P0306 CEL

[AntleredRuin]

It had been having an intermittent hesitation for a couple months on WOT so I changed the fuel filter (OEM) about 2 weeks ago which I'd say about 90% fixed the problem. A lot more responsive across the board.

Then it threw these codes yesterday (P0300, P0301, P0302, P0306) with no new symptoms (still the occasional hesitation but that's it).

I'd been planning an overall maintenance refresh (new spark plugs, wires, air filter, PCV, O2 sensors, radiator flush, etc), so that might still be the best course of action. But I guess my main question is if could be something even more sinister and thus not 'worth' refreshing, if that makes sense.

My fear is headgasket because the codes indicate different unrelated cylinders (not connected via the waste-spark setup, etc) but I have no overheating issues and my coolant level has been rock solid for a couple years.

Thoughts?

 

[Endlessblockades]

260K is a reasonable lifespan for fuel injectors. I had most of those codes, did everything easy* first to no avail. Fresh set of MotorWest injectors and she purrs like a kitten. Plugs is a good time to do a quick compression check with any of the many inexpensive kits available. I wouldn't be too worried.

*Coil packs, wires, plugs.

I had already done fuel filter, PCV, cleaned MAF, new TPS, and Airaid intake when the misfire happened so I ruled those out.

 

[T4R2014]

If you aren't losing coolant I would forget about head gasket issues. To me it sounds like injectors, but it's worth running compression.