C5 X7 2009 PETROL, INTERMITTENT STALING/SURGING/POWER LOSS ??? 15K miles FSH - Please HELP !

[b4mky]

Hello all, this is my 1st post and am keeping my fingers crossed !
I have a C5 2.0 16v petrol with only 15000 miles, it has full Citroen main agent history and just serviced [there did not seem to be any faults then], and they reported on none. I have only just bought the car and it was 1 owner from new.
The problem I have is that every 5-30 miles [occasionally within the 1st mile] also when cruising 50-75 mph [on motorway] or approaching a roundabout when braking or pulling out of a junction [particularly dangerous] the car feels like it is running out of fuel [plenty of fuel in tank] ....... and so I give it some accelerator 1/4 to 1/2 and NO response ... it just stutters between 300-550 rpm, sometimes at the traffic lights/junction if I put it in neutral and can get the revs past 1000 or so it will clear, but the best way is to switch off engine and restart and all is fine again ?
It starts perfectly every morning running on all 4 cylinders, without a trace of a misfire etc, infact the other day I drove on a 40 mile trip, no problems. Parked the car for 15 minutes, started up again [all fine], then drove 1/2 mile slowing down when approaching the lights and it did it again, so put it in neutral started up and all fine. 30 mins later a mini loss of power again , that cleared and all fine again.
I have code read it last week and as follows :
1. U1213 - Deflation detection DSG - Vehicle speed info incorrect value received - Permanent fault
2. P2006 - Gearbox ECU AL4 type - refer to service manual - Temporary fault
3. P0170 - Injection MM6KP - Fuel injection - Permanent fault
4. P0172 - Injection MM6KP - Richness regulation - Permanent fault

....... and so I fitted a Lamda probe - Bank 1 [the nearest to the head] and thought it was better, tested and all was ok, switched off for about 25-30 mins, started all ok smooth as you like, the tried to pull away, initially fine for the 1st 5 metres then no power again. Restart and all is fine ???
So code read with the new probe in [it did have new plugs at the service at Citroen] and slightly different readings.
1. U1213 again
2. P0135 - Injection MM6KP - Upstream oxygen sensor heating command - Permanent fault
3. P0132 - Injection MM6KP - Upstream oxygen signal - Permanent fault

Just to say this is definitely a PETROL version with only 15k miles and has No fuel filter although it sort of feels it is running out of fuel ??
All of your help out there would be most greatly appreciated - Thank you.

[ell270390]

If those are the only faults that return it indicates definitely a fault on that system!. I'd check the wiring from the upstream oxygen sensor to the engine ecu! If that's okay try another sensor you may possibly have been supplied at faulty sensor ! If still faulty after that you'll have to start looking at the engine ecu been faulty

[b4mky]

Hi, Thank you for that kind advice, I'll check the wiring although it has been garaged all of it's life in a dehumidified area. ..... and yes I had not thought of a faulty sensor, good point. I'll do those checks first and report back.
Thanking you again for your time and thoughts - Much appreciated.