Hey all,

I have an absolute lemon of a car here with many parts replaced. Car has 115k miles

Replaced:

• head gasket
• valve stem seals
• Valves were lapped and seated at a machine shop
• 4 injectors, HPFP, fuel rail pressure sensor
• 3 piece Mahle oil rings, cylinder hone
• rod bearings, and aftermarket rods
• thermostat, water pump
• Timing chain kit. Guides, tensioners, sprocket.
• Vacuum lines
• Fuel filter
• Crank sensor
• Valve cover
• New oem battery
• Along with most o rings and seals as I could

Did NOT replace:

• Vanos solenoids (replaced under warranty at 60k and looked clean)
• o2 sensors
• MAF

Cylinder #3 is misfiring much harder than #1.



Got 1 known good coil pack that’s I’ve used to swap around cylinders and no change. Swapped around spark plugs and no change. Still #3 and bit of 1.

Compression test shows 200 across the board with 205 at #3.

Compression ✅. Fuel ✅. Spark ✅. Air ?

I haven’t fixed this minor crack in the intake manifold behind the throttle body. Previous thread titles manifold crack. But my fuel/air ratios don’t seem to be off?? I’d like to do a smoke test but haven’t figured out how to perform it.

Tested back pressure of the exhaust by putting a gauge in the upper most o2 sensor of my stock cat. When above 3k rpms the pressure went past 1.4. Around the 2 psi range easily for an instant when I put the throttle down.

only code I’ve got after swapping coils and plugs around, clearing codes, and cycling key is a 32E2 - P16CF. Electronic immobilizer anti-tampering protection: Expected answer is implausible



if that’s a genuine code I don’t think the car would be starting up. If it’s a wiring/ECU issue I would think there would be far more problems.

I will likely swap injectors around but how would one look for a wiring issues around the DME/ECU before calling for the ecu to possibly be replaced and or re coded.

i do have evidence that the sunroof has leaked before but I’ve since fixed that. The passenger footwell and driver footwell modules look like that have not seen any water damage.

 

How do your intake valves look? It might be time for a carbon blasting of the intake valves. I had some random misfires on my n14, new plugs and coils, didn’t fix, walnut blasted the valves and everything back to normal.

 

had cylinder head out and disassembled. Cleaned and seated all valves.

 

How much run time since the engine work was done?

Not clear to me if the misfire is causing a CEL. Also while a misfire often indicates a sub-par cylinder it can also flag an over performing cylinder. That #3 has higher compression than 1, 2, and 4 suggests #3 is a stronger cylinder. Enough to trigger a misfire?

My limited experience -- actually not that limited in that I worked with consumer and commercial electronic devices like PC boards, railroad track and train controllers, automotive test equipment and residential and agriculture weather stations -- is if a circuit board and its population of components has been exposed to any moisture for any length of time the signs are pretty clear.

Last but not least I'd fix that intake leak. And then make sure there are no other intake (or exhaust) leaks.