On the motorway, admitably going rightly and the car started to slack and go, as if I was tapping the breaks and firing on again, this has happened twice in the past two months, back onto normal roads and it stops, no lights on dash, mechanics a bit mystified also, any opinions? Cheers guys

2007 1.6 TDCi 109ps

96,000

Serviced at 95 (Full)

Timing belt done at 86k

Clutch and flywheel fine (Release bearing whine is all)

Breaks fine, replaced at 94k

Injector seal replaced previous to me buying the car (looking at engine, its the 2nd)

No mechanical modifications, fearful of it being dpf or turbo issues

Was off the road for 3 weeks after I got knocked down, but did it once previous to that, so couldn't be anything relating to that

Hope the info helps, we haven't got the car on the computer yet

Again, cheers for any information

Slight quick update, texted my mechanic about it, he was still working (crazy the hours he does) and said for me to call round, fired it on the computer, brought up:

P0234 Engine overboost condition. Below minimum threshold. DTC present at time of request. MIL off for this DTC. Test complete.

P2458 Diesel Particulate Filter Regeneration Duration. Above maximum threshold. Previous set DTC. Not present at time of request. MIL off for this DTC. Test Complete.

Ignoring this, we believe it could be down to an electrical fault, because as soon as I went to leave, I put the heating, radio and lights on, and it was as if the car was going off the cylinder, so I called my mechanic over who checked the battery and alternator levels (both 100%) But, when he put a load on using the tested, it did it again, tried a few times, did it each time.

So if the alternator and battery are both okay, what could this be? Any suggestions?

I'm going to start by cleaning any visible earths, so if anyone would be so kind as to post a list, it would be helpful.

Cheers again

Why are you ignoring the DTCs? One of the biggest issues is as a result of the DPF filling up, although id expect to see some DPF pressure warnings too, could the dpf affect the turbo? Very much so

I wouldn't say its fair to say im ignoring it when I only found out? Lol

....P0234 Engine overboost condition. Below minimum threshold. DTC present at time of request. MIL off for this DTC. Test complete.

P2458 Diesel Particulate Filter Regeneration Duration. Above maximum threshold. Previous set DTC. Not present at time of request. MIL off for this DTC. Test Complete.

Ignoring this, we believe it could be down to an electrical fault....

Sorry, I must have misunderstood what you was meaning

Mine does this just before a regen kicks in...

Yeah, but the load test would mean its eletrical and not mechanical surely?

You would need to record more data to check that. Record battery voltage over a trip with different loads and see what's happening. These use a SmartCharge alternator so aren't as simple to test as regular alternators.

What is actually happening under load though? Is it 'misfiring' at idle? Or are you driving with the high loads on and its juddering/jerking?

I wouldn't say misfiring, more so idling funny and lurching, as if it was stalling and going again as daft as that sounds

Ah ok, that is kinda normal at idle with heavy loads on, usually called 'hunting', the alternator will struggle to feed them all without a few revs but depends how bad it is. Was it alright when you drove with the loads on was it still jumpy?

Very bad while driving, as if the car was breaking full then accelerating full and it would do this a few times before I got pulled over

Hmm, ok, well it does seem electrical related then as you say.

Really need to get some live diagnostics on it to go any further.