[Judder]

I'll explain this the best I can, I've had pretty much trouble free motoring from new, only changing parts as necessary, the car has 140,000 miles, however, in the last few weeks I've a drop of power/stuttering when accelerating from gear 2 onwards.

When out of gear and rev, no issue, no lag, when pulling off in 1st gear no issue, when changing into second, if the revs are low in the range 1.5/2k  it sort of stutters, drop of power probably from ecu control.

The fuel filter was changed as part of the service 5 months ago, I changed the maf a few days ago, suspecting it could be that.
The injectors were tested and are all fine.
There are no errors in the diag.
I had a carbon clean where the egr was being monitored, when the engine was revved it looked like the flap was opening and closing, so whilst it could be that I just don't know where else to look.

Has anyone got any thoughts? or would like me to provide more information to help? or any tips on how to identify the fault or narrow it down?

[Judder]

Anecdotally, the loss of power is worse when cornering.

[Judder]

The fact there there are no sensor or other faults, would that point to it potentially being a fuel pump issue?

Or, has anyone gambled threw bits at theirs, I’m thinking egr and or lambda sensor.

[Paul T]

I have a similar problem and it appears to be the O2 sensor sooting up, if I leave it for a while the engine management light comes on and then when the dealer blows out the sensor the management light can be reset. They either don't know what causes it or if they do, they won't tell me, which I find quite suspicious.

[Judder]

So o2 sensor is in the mix, yours throws an engine light though. Whereas mine throws no lights or faults.

Has anybody got any ideas on where to look first?

[Judder]

To keep adding to this story, from a cold start it hardly does the stuttering/loss of power and it definitely gets noticed and worse when it warms up.

The mpg is well down too, my average mpg (when not on a run) was about 45, this has reduced to around 38, around 70-80 mile less on the full tank.

[Judder]

It was doing at 2200 revs at 70mph.

I put a tank of shell vpower diesel in, that seems
To have made it worse/more pronounced.

Has anyone got any ideas whatsoever?

[Cry-30]

Cheap ideas...

A. Drain out the fuel filter incase it's full of water and some is being dragged in.

B. Change the Air Filter unless obviously clear.

C. Whip out the O2 sensor on the top rear of the engine and give it a EGR cleaning fluid clean.

D. Check power to the fuel pump is solid and steady.

Expensive ideas...

A. Replace your fuel pump.

B. Replace the o2 sensor.


Have you got a cheap EML reader? worth checking a few bits and pieces.

[Judder]

@Cry-30 i have a reader I can put in the obd port
There are no errors. What would you suggest I look
For?

[Cry-30]

Do a live info map and see if anything drops off oddly.

A very simple o2 sensor clean though would be my 1st call. Mine had the 3k rpm limit and a few EML lights and a new o2 and fuel sensor got rid of it all.

But if the fuel pump is getting weak, 2nd gear up would start the messing about.

[Judder]

It does it in all gears, just not noticeable
If you floor it. It’s worse at like 30mph in 4th at low revs.

[Cry-30]

That screams low fuel pressure. Cheap try, Fuel filter.

Actually, as it's already been changed, worth whipping the bottom sensor out the fuel filter and see it it's got any water/contaminents in the filter base. Then, re-bleed the fuel system fully.

[Judder]

I got a replacement genuine second hand maf from
EBay incase the replacement aftermarket one has issues. There is oil in the pipe going from the maf to the turbo.

[Judder]

Smoke test passed,  no leaks.
I’m really at a loss, there are no errors whatsoever.

[I30 GD]

Is the exhaust pipe sooty or clean?

[Judder]

I think it looks sooty, however, I’ve never ever looked at it before.

[I30 GD]

Exhaust pipe should be clean if it has a dpf, get a diagnostic on it read the dpf pressure and regeneration intervals, mine was full of ash at 112k miles and needed cleaning.

[Cry-30]

Need to see what the fuel pressures are like.

Worth increasing the Cetane in the fuel which will increase the temps and help clear out the dpf.

[Judder]

Exhaust pipe should be clean if it has a dpf, get a diagnostic on it read the dpf pressure and regeneration intervals, mine was full of ash at 112k miles and needed cleaning.

One of the first things I did was get a carbon clean, that didn’t make any difference to the issue.

I’ve an obd2 an elm327, this doesn’t seem to be able to read the dpf pressure, so I’ll have to get the garage to do it, at every interval nothing has seemed out of tolerance.

[Judder]

Need to see what the fuel pressures are like.

Worth increasing the Cetane in the fuel which will increase the temps and help clear out the dpf.

The fuel rail pressures all looked ok from the diagnostics . I’ve tried additives in the fuel, these haven’t made any difference.

[Cry-30]

Rightio. If the pressures are fine, it may be flow rate. For £20 odd, it's daft not to swap the Fuel Filter again "Just in case".

[I30 GD]

Exhaust pipe should be clean if it has a dpf, get a diagnostic on it read the dpf pressure and regeneration intervals, mine was full of ash at 112k miles and needed cleaning.

One of the first things I did was get a carbon clean, that didn’t make any difference to the issue.

I’ve an obd2 an elm327, this doesn’t seem to be able to read the dpf pressure, so I’ll have to get the garage to do it, at every interval nothing has seemed out of tolerance.

Elm327 should read dpf pressure, what software/app are you using?