Engine loses power, cant idle, no acceleration

[Robvenning]

Hi, a week ago i was on the open road and my triton MQ decided to knk out. It lost power, the engine began to sound incredibly rough, it would really accelerate past 1500rpm and when i came to a stop it was idling very rough and the cut out and struggled to star again. A while later the problem disappeared and then came back very quickly.

I sent it to the dealer, they serviced it (i have no idea why), checked and purged the fuel system but concluded that there was nothing wrong with it because the computer was not throwing any error codes (not 1). I picked it up and the same thing happened, they apparently then cleaned all of the sensors in the engine, (MAF, MAS, fuel and checked the EGR, DPF and fuel pump. Everything is working fine.

Has anyone had any similar issues?

Its got 164,000km, its a 2017 glx A/T with super select and the high power engine.
I installed the following:
Mann/Hummel catch can
Fuel manager
torque converter lockup switch.

Anything will help as the dealer has no idea what to do and ive spent enough $$ already.

Cheers,
Rob

[FQCODEL]

When was the last time you replaced both fuel filters?

[RHKTriton]

Sounds like dodgy connectors on some sensors and/or possibly sticky SCV.

If it's going ok now - leave it alone.

I'd have some MAF sensor cleaner, dielectric grease and pair of long nose pliers handy, ready for when it might happen again.

Problem with each new generation of vehicle is the added collection of sensors and associated control modules. The days of fuel, air and "spark", ( compression )are gone. You now need a Shrink to look after the vehicles "feelings". lol

[Robvenning]

I changed both fuel filters around 10,000km ago. They checked the MAF, the SCV, the EGR, DPF and purged the system again and it didnt help the issue.

Im taking the truck to another mechanic today. The trouble is that there are no error codes so the dealer has simply given up.
I'll post any developments.

[DibbyDibbyDJ]

I bet they didnt check the EGR. Its in a pig of a place, and they just plugged the MUT in and looked at the feedback from the motor. The actual valve is not connected to the motor, It is pushed open by it, but spring pressure closes it, with the motor retracting by itself. So whilst the EGR motor gives feedback that it is closed. Physically it could still be open, caussing your symptoms.

On inspection of the valve itself, you would see scoring on the shafts. Even though the shafts are carboned up, a clear line up the shafts length will be visible.

To confirm its the EGR i would remove pipe to the inlet and slide a thin piece of tin in to block off its port, then retest.

This isnt a common fault on MQ, but i have seen a couple do it. More common on outlander and ASX, but they all have the same design EGR.

Worth a try IMHO

[Robvenning]

Hello, an update:

I sent the Triton to another mechanic (who has done my classic cars for years), he found the problem immediately on his much more generic scanner. It was a code that indicates a fault with the Throttle Position Sensor, he tells me that this can cause all of the symptoms that I have describes to him. It was a "hidden" code but I'm really surprised that they couldn't figure it out at the dealer.

Hopefully this is the issue.

[Robvenning]

This will sound strange but what was causing a lot of issues including this one was my scan gauge. Lots of strange things began to happen with the vehicle (no gauges, rough running, etc) but no check engine. I disconnected it yesterday because I thought I'd give it a try and everything is back to normal (except a check engine code relating to the fuel pressure sensor in the filter) very odd.

II've had the scan gauge for about 7 years, in three different cars and it never gave me issues so im not sure what to make of it.

[RHKTriton]

As stated in another thread, my plug in HUD really affected things. Intermittent low power, cruise dropping out. Of course your not going to see it with a scanner as you have to free up the ODB socket.