DTC Fault Code P0300

[Downesy]

Hi,

Chasing some help please.

I was driving today when the car surged a little and the DTC code P0300 (Random/Multiple Cylinder Misfire detected) popped up. The car seems to idle and drive ok with little to no smoke from the exhaust, but every time I clear the fault it re-appears and the engine light comes back on.

The car is a 2011 SR5 Diesel Hilux, 76,000km on the clock.
The car has been remapped and has a stage2 Gturbo fitted, but that was a few years ago with no issues until today.

Any info on what you think the issue could be, would be much appreciated

[VtSg92]

Have you checked the fuel filter / changed the filter? Similair thong happened with my 2012 SR and a simple fuel filter change fixed the issue.

[Downesy]

Yeah, I replaced that yesterday hoping it was just that.

It was a bit dirty but not too bad because I only replaced it 5000km ago.

I googled the fault but there is not a lot of info around related to Diesel engines,it is mostly related to petrol engines and issues with spark plugs/leads/coils etc.

This is all I can find on the net and not sure where to start:

Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve Faulty catalytic converter(s)
Faulty camshaft position sensor
Defective computer
Low Fuel Pressure
Vacuum Leak
EGR system malfunction
Internal Engine Problems (such as low compression)

[telliscope]

Multiple misfire would indicate the fault is evident across all cylinders, would be looking at components which affect all cylinders ie - supply pump, egr, cam sensors etc did it begin after recently filling up??, I would be checking fuel quality first.

[Downesy]

It has 3/4 of tank of fuel in it so possibly and the fuel in the northwest has been known to be pretty average.
Is there an easy way to drain the tank or should I try adding some fresh fuel to try help dilute the possible shit fuel?

The EGR was disabled when the car was remapped a few years ago. (I did a intake/egr clean then also)

Is the cam sensor that unit at the front top of the engine near the pulleys?

[telliscope]

No easy way besides dropping the tank unfortunately. I would be checking fuel condition first and if questionable I would be doing that first and go from there. Normally a cam sensor issue would trigger its own code.

[martynvella]

It's going to be an electrical problem. You would notice multiple misfiring. Find out what sensors generate that code and follow the circuit all the way to the Ecm looking for for corrosion.

[Downesy]

Ok dropped all the fuel out of the fuel tank and added new fuel, filter and some fuel cleaner, problem still there ...

Only sensor I think could cause the issue is the cam sensor?