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[JamesV6CDX]

My 3.2 has covered the last 10k miles without missing a beat, including a trip through France and Spain down to Gibraltar.

Last night, SWMBO was driving it, stopped to call me at a garage and said it was "holding back".

This morning I went out for a look. Plugged in the code-reader, and there was one "pending" code for Short Term fuel trim - bank 1.

Tried to start the car, quite a bit of turning over and then it fired. I left it to idle, and it was hunting... revs going up and down consistently on their own. Not misfiring though.

Took it for a drive, went ok through the village although felt underpowered. Got to a bigger road and gave it some more throttle, and it completely bogged down, with the throttle down hard, there was no power at all, but as soon as I eased off, it would gently cruise. I did on a couple of occasions managed to get it to rev much higher, but it won't do it every time.

Compressions are all good.
Plugs all good.
No code 19.
No recent work on the engine in the last 10k miles, so nothing recently disturbed to introduce any big air leaks. Vac / servo pipes and bagpipes / trumpets etc all in place correctly.

I am now thinking fuelling issue? Pump in the tank?  I don't think these are clever enough to give a live data fuel reading, as no sensor on the rail, is it worth me getting a manual fuel pressure testing kit? This may make it awkward to view it whilst under load - which is when the symptoms are most evident.

Any other suggestions please? I did once look at a car for a chap with similar symptoms and he was tearing his hair out, turned out there was something large and dead in the air intake - so that's worth a look too I guess!

[JamesV6CDX]

When I put the foot down and nothing happened, it felt JUST like running out of fuel.....  I should add, tank is half full. And no, she hasn't put diesel in it 

[Doctor Gollum]

You'll never get a 2 digit code off a DBW car.

Any improvement with the MAF unplugged?

Weak/failing fuel pump would cause that type of behaviour.

[JamesV6CDX]

You'll never get a 2 digit code off a DBW car.

Any improvement with the MAF unplugged?

Weak/failing fuel pump would cause that type of behaviour.

Yes sorry I know it’s a 4 digit on DBW  - I just meant the equivalent code in old money

No different with MAF unplugged

For some months it’s misfired upon cold start but then clears immediately if turn off and back on 

[Migv6 le Frog Fan]

Fuel filter ? 

[YZ250]

Fuel tank pump getting lazy or pipes deteriorating in tank?   

[TheBoy]

Live data it. Are the trims bad on both banks?  In particular, are the LTFT's moving off 0%.  If just on one bank, look for air leaks only impacting that, on both intake and exhaust, but also don't rule out the primary O2 sensors itself on that bank. If both banks, look for leaks that impact both banks, or MAF.

MAF at idle should be around 12-13kg/hr for a 3.0/3.2 with A/C off. Add around 1kg/hr if your A/C still works and is on.

[JamesV6CDX]

Live data it. Are the trims bad on both banks?  In particular, are the LTFT's moving off 0%.  If just on one bank, look for air leaks only impacting that, on both intake and exhaust, but also don't rule out the primary O2 sensors itself on that bank. If both banks, look for leaks that impact both banks, or MAF.

MAF at idle should be around 12-13kg/hr for a 3.0/3.2 with A/C off. Add around 1kg/hr if your A/C still works and is on.

Thanks TB, I did look at the data values, LTFTs appeared fine from memory, and the MAF readings around about 12kg/h

[Raeturbo]

A vacuum gauge could help here👍

[Raeturbo]

https://www.classiccarhub.co.uk/articles/tuning-and-fault-finding-using-a-vacuum-gauge.html

[cam.in.head]

not sure how it compares but mine runs at 2.5 g/s although its a 2.6

[TheBoy]

not sure how it compares but mine runs at 2.5 g/s although its a 2.6

g/s x 60 x 60 / 1000 = kg/hr

So in your case, that's 9kg/hr which is slightly on the low side of OK - a 2.5/2.6 is usually around 10-12 with a/c off

[cam.in.head]

doesnt seem go have any issues. mpg is good ,runs find and mot emmidions are fine but i will look into if theres any air leaks as the ltft's are on +2.5 ish . cheers .

as regards the posters issue definately worth doing a fuel pressure check as it does sound fuel related

[TheBoy]

the ltft's are on +2.5 ish

That is a issue assuming it's not LPG converted

[cam.in.head]

well this is typical of my luck !   i comment on someones post and end up finding out my own car has a problem i didnt know existed . i was always under the impression that up to 10% ltft was normal . think i even read it on here somewhere over the years . whatever it is its obviously not a major fault as the car runs absolutely fine . rock steady idle ,mot emmisions spot on and fuel consumption is ok too ( not that i have owned another 2.6 to compare it to )so i wont be worrying too much but if its supposed to be zero ltft il investigate a bit !!