Very odd. Havent driven the car much due to the snow but have now noticed when planting the throttle the boost comes in then fluctuates at the top end, you can feel it increase/decrease and the car pull back and lurch forward.

I havent checked the fault codes but nothing has flashed up on the dash - will there still be one?

Engine is completely standard since the remap 3 1/2 years ago with 70k on the clock and is running the standard DV since the remap without any issues. Has had 4 coilpacks about 20k ago.

Engine idles fine, revs perfect under no load and drives well under part boost, the top end though is annoying under WOT. Maybe even fuel problems?

Any thoughts would be welcome - Ill check plugs and coilpacks too.

Andy

Edited 29 December, 201015 yr by Liverpool-Lad

worth checking maf and n75 valve.

Thanks, how can I troubleshoot these? Visual checks are OK and I cant see any issues with the connecting pipes or wiring.

Edited 29 December, 201015 yr by Liverpool-Lad

It's worth checking the DV, as the OEM DV is prone to failure. Remove it & push the piston up, then put your finger over the small pipe on the top & release the piston. The piston should stay up until you take your finger off the top.

N75 failure is pretty rare & can be difficult to diagnose unless you have a known good N75 to compare it with.

Unplug the MAF & go for a run, if the car feels better you have MAF issue, which can sometimes be cured by cleaning the sensor in a freezer bag filled with Isopropal or carb cleaner.

Well, unplugging the AFM made no difference after a test run. Also, could not feel the turbo do anything at certain stages/gearchange up until high revs.

Possibly boost solenoid?

I have the same fault as you mate especially in top gear..lower gears seem ok but it just boosts on and off in 4th and 5th gear

If you find out what it is let me know!!

I will do. Have you found in any gears even from low speed the turbo is always there? Mine wasnt I found.

We hink its the N75 valve...will this fit chaps?

http://cgi.ebay.co.uk/N75-valve-standard-version-058-906-283F-Genuine-/260701954812?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3cb30c22fc

This is getting odder. The EML doesnt show on ignition startup - Ive seen it in the past when the coilpack went but not now. When the MAF was disconnected the traction control light stayed on.

Is the EML next to the oil pressure in the middle bank of lights?

Going to scan for fault codes anyway tomorrow with a Snap On Solus.

EML is in the centre of the speedo, bottom left next to the 20 km/h. Should light up when the ignition is on then go out once the car is started.

Thanks for that. I can see the outline when shining a torch over it but dont see it when the ignition is on.

Update - car has been on the scanner, showing misfires on 1 & 2 plus multiple misfires also.

Id be very suprised if it was the coils or the plugs to all go at the same time? Stranger things have happened I guess. Even tried filling the tank with V power from another shell garage (in case the last tank of V power was dodgy) but no difference.

Any other thoughts? Plugs are on order but will swap around coilpacks tomorrow.

OK, thought the issue was cured after swa[[omg the plugs a few weeks back for NGK BKR7EIX, but the issue is coming back intermittently. On the odd occasion also in some gears under full load there is NO turbo at all?

Other times it feels OK with some minor stuttering under full load.

Any ideas?

:(

Fuel filter? Might be blocked if it's having issues at full power.

Ive actually got one here.

Im not sure that explains why sometimes it feels like an NA car with no boost and the next has all its power back?

Ill fit it anyway.

fuel pump might be on its way out

try fuel filter first as this could be the issue as said above

Also, what should the plugs be gapped to? I didnt gap them as the last set were in for 25k from the box (same make/type) without any issues.

Cheers.

should always check the gaps as they can from new be different ( but thats not the problem )

as for feeling like a na it will if its not being fed enough fuel the ecu will see this and pull boost and timing right back like limp home mode as such will cause it to feel slow

Edited 28 January, 201115 yr by westallc

Got a similer problem with mine at the mo but the signs are its a boost leak might be worth checking the hoses for splits.

Are your symptoms consistent? Mine seem to vary widly between an NA car in some gears and then full power. Very weird.

Update - fitted genuine filter which looked rather manky and I think that may have sorted it! Fingers crossed.

Ill keep you posted but the signs are good. Cheers guys.

Actually, no.

misfire on #2 and random multiple misfire. Does this mean solely cylinder 2?

Ive tried some 2nd hand coil packs from before I had all 4 changed 4 years ago and still the same error. Think its worth trying some brand new coilpacks? Seems to be worse in 3rd & 4th.

Interesting.

Ta guys

Edited 29 January, 201115 yr by Liverpool-Lad

you need to check the wiring to coilpack 2 could be damaged causing the issue

Wiring looks OK on first glance, I dont suppose there is a replacement loom for all 4 available?

Had a quick look and there is some insulation missing near the coilpack plug.

Edited 29 January, 201115 yr by Liverpool-Lad

It may be that the wiring has started to crack, especially with it being an older vRS. Apparently, there is a re-wire kit available (it's a big problem in the US)