Hey gents, I was out taking my 3.0 on a long drive today and ~10 minutes away from home, I had a sudden loss of power. Very very laggy throttle response (think ~5 seconds to get anywhere close to redline with heavy throttle). Luckily I was able to limp it ~1/4mi to a parking lot, where I was able to scan for codes. Tried starting the car with the MAF disconnected, but no change.

1. The car came back with codes for P0300 (random misfire), along with misfire codes for Cylinders 2, 4, and 6.
2. The car has new upper and lower intake gaskets (replaced ~1mo ago if I remember correctly). Along with 6 new spark plugs, IMT O-Rings, and relatively new injectors (replaced ~1yr ago with OEM ones).

Any ideas what could be causing a full bank 2 misfire?

I felt both of the black plastic vacuum lines that connect to the top of the manifold, but couldn't feel any vacuum getting pulled, hear vacuum, or feel any cracks in the lines. The large rubber PCV line had no obvious flaws, but I'm probably going to pull it off to inspect it. Looking at the electrical diagram, I see no commonality between coils for Bank 2 that aren't also shared with Bank 1... same for the injectors. I see no possible way that that all 3 front coils and/or injectors died at the same time either.

 

Went and towed the car home today. While unloading it from my trailer, I noticed the brakes are.... near nonexistent. No fluid leaks, level in the resorvoir looks good.

Still misfires extremely badly, misfires on all front bank cylinders.

Highly suspecting vacuum leak.... but after spraying down the plastic lines that are usually broken, along with the IMT valves (in case the new o-rings weren't sealing), PCV line, and as much of the upper/lower intake area as possible... I'm unable to find one. Debating on pulling the intake again to give the stuff under there another inspection.

I don't wouldn't think it's the red Induction vacuum line that goes to the rail since I'm only getting a misfire on the front 3 cylinders, and IIRC that line connects to the area of the plenum that feeds the rear bank... So if it were broken, I'd expect misfire codes on the rear bank moreso than the front bank?

 

Welp, figured out what the problem is. The lower portion of the front valve cover, the plug wells, and the bottom of the aribox were all filled with water...

Not sure how considering it was a clear day, some light rain in the morning... I'm missing that accordion air horn thing that connects to the front/bottom of the airbox... Maybe road spray from cars ahead early that morning?

I'm quite honestly perplexed. I sucked out as much water as i could and I'm letting it all air dry for the rest of the day. Will report back tomorrow and see if the car is fixed (I don't see why it wouldn't be). Still unsure how it happened, the engine bay has never been "washed" with a hose/pressure washer, I haven't left the hood open in a heavy rain either...

 

Yup, as expected the car is perfect once more, drove for ~50 miles today. Had to spray out the coils and plug wells with some electronics cleaner to make sure they were completely dry.