Loss of power while driving

[Ericthetreeguy]

Hi all new here but have had an issue with my 2012 Mk7 dropside and would be grateful for any help pointers as the internet has thrown hundreds of different could be issues my way so far.

I'm handy with a spanner and have a basic understanding of engines however I'm not a mechanic.

The issue may have started a while ago but has only been subtle so I haven't really noticed or it could have started in the last few days.

I was lowish on fuel 30 miles left in the tank and filled up in the morning. Drove fine going to my first and second job (about 20miles) then driving down a duel carriageway at 60mph the 'Engine malfunction' message popped up and the power dropped to the point getting past 50 was a struggle. Got to my destination turned engine off and started back up all was fine, no 'Engine Malfunction' message no loss of power.

The next day the same thing happened later on, but managed to keep going.

Yesterday I drove 80 miles no issue, got back to my yard in the afternoon and as I left the engine warning light came on and the power just seems very poor. engine light has stayed on and the issue continues. I have been driving it as it seems to be coping but a little worried the problem will get worse. I am going to run through some simple things tomorrow but has anyone got any ideas what might cause this?

Its almost like I have loads of weight in the back and it can't seem to accelerate on hills.

I asked a friendly mechanic I know if he had any idea and he kindly ran a diagnostics for me and the only thing that showed was glow plugs but I have had no issues whatsoever with starting, only issues are while driving.

Another thing I will add, possibly unrelated and my throw people off the scent but I have had a couple of times in the past 6 months where I have been sat at a set of lights or junction and the engine has revved violently as soon as I put my foot on the accelerator. maybe 3 times over the last 6 months.

Any advice will be greatly appreciated.

Thank you in advance.

[the dutch guy]

Have codes properly read. If he trew it into limp mode under driving you must have more codes then just glow plugs.