Looking for advice and tips, been reading thru the various reports on P0301 ~ 04 codes. Here is the deal with mama's little crusier. It is a very stock 2009 LS with the 2.2 ecotec, sitting about 105K. About six months back it started spiting a P0304 code, intermitantly. At 102K it started to set more frequently, so I replaced the plugs. That seam to help for about a week, then the code came back HARD. All this time it still runs smooth, fuel economy still good. Swapped the coil packs, with no effect, figured I would take it to the dealer, I didn't want to mess with the fuel injectors.
Dealer comes back with low compresion on #4, reading 30psi, rest are at 150psi. They immediately want to pull the head. I politely refused at that point, wanted to check my options. When I got to the dealership to pick it up, I asked the service writer if they had oiled the cylinder to eliminate the rings, he looked at me ilke I had grown a second head all of a sudden.
Long story short, I ran the compression test myself, along with a leakdown test. Found that the #4 exhaust valve are leaking. Found a great troubleshooting video here:
Remember this is a stock mom car, what do I need to think about on a head rebuild. A local shop I called quoted me 180 to run the head. Timing Chain? Thermostat? Any tips or tricks would be greatly appreciated. My last rebuild was 25+ years back. Thanks for reading!