Chugging when accelerating

[young_fogey]

116bhp CDT. When accelerating in 5th from about 50-60mph, around the 1700-1900rpm mark, my car chugs quite violently and the rev counter flickers wildly. This only seems to happen at that precise speed, when accelerating fairly briskly and usually up a reasonable hill. When accelerating normally, e.g. joining a motorway or something it doesn't seem to happen. But in those specific circumstances (and it really is only in those circumstances) I think its getting worse. Not that difficult to live with, either easing off a bit or accelerating a little more so the autobox drops into 4th stops it. It almost feels like it happens as soon as the turbo kicks in, over 2000rpm it is not there, when at steady speed, at any rpm it isn't there.

I've not touched the MAF or PCV since I got it. Could it be one of those? But it doesn't seem to have any of the other characteristics of a faulty MAF sensor and the MPG is excellent (45mpg average, sometimes more, rarely much less). Surely it isn't just the autobox choosing an inappropriate gear for the incline causing the engine to labour?

Any ideas?

[Sector-9]

I believe the rev counter gets it signal from the crank sensor (via the engine ECU) - see if you can get some kind of diagnostic tool that records live data to see what the engine ECU is reporting for revs at that speed, though I find it hard to believe a problem with that sensor would only cause that particular issue

[SCP440]

It might be worth putting some Forte injector cleaner through it, I had a similar problem with my Transit and a dose of the above and it is now back to normal if not better than it has been for a while.

Put it in at 1/4 of a tank and drive it like you stole it for 20 miles and then let it sit for a day or so. Then put some Ultimate in and see if it helps.

[young_fogey]

It might be worth putting some Forte injector cleaner through it, I had a similar problem with my Transit and a dose of the above and it is now back to normal if not better than it has been for a while.

Put it in at 1/4 of a tank and drive it like you stole it for 20 miles and then let it sit for a day or so. Then put some Ultimate in and see if it helps.
Thanks. I did put halfrauds injector cleaner through it a while ago when I first bought it as it wasn't idling evenly, I'll try that again.

[murphyv310]

Could be a bit of fuel starvation, Perhaps fuel filter or pumps.

[stevenicks]

I had a problem similar to this, turned out the clutch had gone :shrug:

[young_fogey]

I had a problem similar to this, turned out the clutch had gone :shrug:
Mine's an automatic!
Could be a bit of fuel starvation, Perhaps fuel filter or pumps.
Filter has been replaced recently, not sure about pumps though.

Is the general consensus that it is unlikely to be the MAF or PCV?

[stevenicks]

Sorry :duh:

[young_fogey]

It might be worth putting some Forte injector cleaner through it, I had a similar problem with my Transit and a dose of the above and it is now back to normal if not better than it has been for a while.

Put it in at 1/4 of a tank and drive it like you stole it for 20 miles and then let it sit for a day or so. Then put some Ultimate in and see if it helps.
Amazingly I've had some success with this, thanks. Put some injector cleaner in and hooned it about it sport mode for a day or two. Not cured completely but the chugging is now more of just a vibration, and I now have to try harder to actually get it to behave like that at all. I've put a tank of optimax (or whatever its calling itself these days) in it too now, so we shall see if it improves anymore. Still quite a difference though.