5.0 TVS DTC P0300 on 15 VMP GT500 config

[G-Town-GT]

Hi,

Pretty goofy thing, the issue appears always under the same condition around 4700rpm in 5th gear pull.
The issue does not appear in the lower gears while rpm increments faster there.
As it is not a P0301 - 308 it does not point to a specific Cylinder.
I already heard voices that said ignore it.... !?

attached logfile shows the area of DTC appearance between 3:41 and 3:42
There seems to be a fuel system fault at around that time, but I do not see feel any hesitation of the engine or similar.
This may also be caused by the DTC it self...!?




Freeze Frame: 0
DTC: P0300 - Random Misfire Detected
Number of Emission Related DTC: 0
Fuel System Status: 02 00
Calculated Engine Load: 100 %
Engine Coolant Temp: 88 ?C
Short Term Fuel Trim Bank 1: 4,6875 %
Long Term Fuel Trim Bank 1: -13,28125 %
Short Term Fuel Trim Bank 2: 4,6875 %
Long Term Fuel Trim Bank 2: -10,15625 %
Engine RPM: 4734 rpm
Vehicle Speed: 191 km/h
Timing Advance: 23 ?
Intake Air Temp: 38 ?C
Mass Airflow: 359 g/s
Throttle Position: 76,8627450980392 %
Run Time Since Engine Start: 217 s
Commanded EVAP Purge: 0 %
Fuel Level Input: 23,5294117647059 %
Warmups Since MIL Clear: 0
Distance Since MIL Clear: 7 km
Barometric Pressure: 117 kPa
WB Lambda 1: 66 CA 7E AE
WB Lambda 5: 65 F0 7E 76
Catalyst Temp B1S1: 961 ?C
Catalyst Temp B2S1: 961 ?C
Monitor status this drive cycle: 00 47 80 E5
Control Module Voltage: 14 V
Absolute Load: 149,411764705882 %
Commanded EQ Ratio: 0
Relative Throttle Position: 63,5294117647059 %
Ambient Air Temp: 33 ?C
Absolute Throttle Position B: 88,2352941176471 %
Accelerator Position D: 78,8235294117647 %
Accelerator Position E: 39,2156862745098 %
Commanded Throttle Actuator: 100 %
Fuel Type: 01
EVAP System Vapor Pressure: 32718 kPa

[Jn2]

I looked over the log and it's hard to tell what you are commanding for PE fueling. You seem to be hovering around .82λ, but commanded never seems to be .82λ. I also noticed your fuel trims on average sit in the -10 range. Correct the MAF to and get it within +/- 2%. Also try lowering PE WOT fueling to .78, less chance of preignition or misfires the cooler you run the cylinders...

Screen Shot 2017-03-28 at 2.00.27 PM.png


Also are you running 1 step colder plugs or stock, what are they gapped too? It's going to hard to nail down the cause of a random misfire since it doesn't tell you which cylinder it was, it could be anything from a wet or dirty MAF, to bad coils, or bad plugs etc etc....

[G-Town-GT]

Thanks for your reply,

fuel trims are in order now, Maf was corrected.
Colder plugs are in there gaped to ,35

yes it can come from anywhere, but it is only in 5th gear - very strange.......

[Sweet35th]

I would assume you have, but sometimes we all overlook the most simple solution........Have you performed a crankshaft misfire profile relearn?

[G-Town-GT]

No Crank relearn up to now, thought about it , mybe I'll give it a shot.

[kaineoutlaw]

Do you have a working tune for a vmp 15+ car?