Slight midrange miss under load TD4

Hi all - I have been trying without success to get rid of a slight what feels like a miss at about mid range rpm 3000rpm under moderate load.

TD4 running sweet otherwise - changed Crankcase breather for BMW one also done EGR blanking with full replacement kit. New intercooler hoses. Stripped MAF and cleaned it. New Air filter. Injectors have been out as one started leaking because the collar stud broke off (rusted) - all were taken out and generally cleaned and new collar and studs fitted. All electrical connections to sensors pulled off and checked - no signs of problems.

Basically it accelerates very well through firsthand second then when you go through the midrange it feels like a "wobble" then when you get to 5 th and are cruising at say 70mph I sense it is not running properly on all cylinders - accelerating in 5 th then induces the "miss" - it will go on through to 90 plus but you can feel it is not pulling as it should.

Short of swooping out an injector one by one I don't know what to try next - any ideas? Would a knocked MAF give these symptoms?

Cheers

when my maf packed in i ran it without it plugged in to identify what was causing the fault and it pulled like a train. try it

when you say injectors generally cleaned, do you mean ultrasonically by a specialist, or just wiped over ?

had this with mine at around 2000 to 2500 revs. Tried injector cleaner, which reduced the problem a bit, but you could still tell it was there.

Then, two weeks ago, had my fuel pump replaced, so far, no sign of the "missing", and pulls a lot better too (maybe just my imagination...)

Optimus Prime said:

when you say injectors generally cleaned, do you mean ultrasonically by a specialist, or just wiped over ?

had this with mine at around 2000 to 2500 revs. Tried injector cleaner, which reduced the problem a bit, but you could still tell it was there.

Then, two weeks ago, had my fuel pump replaced, so far, no sign of the "missing", and pulls a lot better too (maybe just my imagination...)

Click to expand...

Hi
No the injectors were just wiped over - the guy that did it is a good mechanic ( ie doesn't make me spend unnecessarily but in hind site it might have been better to have sent them away)

If anything it feels like over fueling as the mpg is not brilliant - 33mpg driven normally tank to tank checking.

It is a bit better after 3 tanks with cleaner but it may be I have adapted driving style.

New pump seems expensive so want to try and avoid that.

I will try the MAF unplugging and see what happens today.