[wertygrog]

Hi there, looking for some advice. My '07 Automatica has had VERY intermittent Cyls 1 & 3 (plus the "random misfire" code) for years. The blinking CEL would happen at idle or coasting only, and wasn't anything I could feel from the driver's seat. It always went away after a few days on its own. No other codes related to camshaft angle or anything else. No variator rattle (repair was performed under previous ownership).

However, this week the problem has come back with a vengeance. The CEL is blinking constantly, and the idle feels/sounds somewhat rough.

What I've tried so far:
-Swapping spark plugs around
-Swapping ignition coils around
-Checking for vacuum leaks
-Cleaning variator solenoid connector
-Cleaning MAF
-BG44k through fuel system

My OBD scanner "live data" shows the car is in "Open Loop - Faulted" mode. For some reason I can't see the upstream O2 sensor voltages on either of my scan tools. However, I can see the downstream O2 sensor voltages and they are very low (almost 0V). STFTs are 0 (since I'm in open loop), and LTFTs are both less than 5%.

At this point, I am not sure what to try other than:
-Check fuel pressure
-Check compression
-Another Italian Reset
-Pull plugs (again)
-Borescope cat
-Try driving around with disconnected solenoids

I could use some advice before I start shot-gunning parts at this. Right now, I'm suspecting it could be any of the following: injectors, cat, O2 sensors, crank position sensor, cam position sensor, variator solenoid, MAF.

Thanks!!
Brent

 

[[email protected] Enzo`s Atlanta]

I would start with checking compression on that bank..It's not going to be a cam or crank position sensor as that would affect more than just two cylinders...Same with variator or VVT issues...Jason

 

[wertygrog]

Quick update.

I performed a compression check and didn't find anything of concern. I checked Cyls 1, 2, 3, 5, and 6 and each were between 180-200psi. I did find that the Cyl #3 spark plug was quite loose. Plug gaps seemed a bit too large (~0.030"), so I tightened them up a bit.

O2 sensors looked fine, and the cats looked fine too (see borescope picture below).

After putting things back together it's running fine now, no rough running or CEL. It's hard to believe anything I did would have fixed the issue. Same as other times this has cropped up...I fiddle with some stuff and it goes away for about 6 months. So any other suggestions are welcome!

 

[beeton]

Cylinder 3 plug may have been the culprit (but as you changed them, maybe not seated correctly due to dirt under the copper gasket...speculating here) or you have an intermittent wire issue on bank 3 that comes and goes with vibration. I occasionally get a misfire on 3 code during damp mornings or during a random drive. The first one scared the jeepers outta me but I just clear the code when it does come up (twice a year) and idle, performance never seems to suffer.

 

[Billydv]

@wertygrog
Just a couple of things, I went through the very same thing. Absolutely couldn't figure it out. Only reason I found it was my wife's Mercedes was pinging terribly, we both use the same gas station.
Try emptying the gas, just drive until you are way down, fill with premium from a reputable gas station and use a fuel injector cleaner. By the time you refill the 2nd time your problem may be gone