td4 flat spot

hi guys
my td4 has 113k on clock just been fully serviced egr buy pass pipe fitted new intercooler pipes starts first time & generally funs sweeet @ 40mpg
but it has a flat spot/ slight hesitation at light throttle eg when crusing if i put my foot down it goes away
any idears please

this sounds a tricky one ,always difficult to diagnose without actually being there could be so many things ,start by checking the easy things
1,check all the vacuum pipes , - they rub and cause leaks
2,inspect / clean egr valve /blank it off, is it seating ?
3, air box, remove and clean, , check/clean map sensor while you have airbox off
4, turbo hoses, , they rub and can leak
5, turbo vane actuator linkage, make sure its not siezed
6, fuel rail connections at the plug,

all the above cost nothing , and wont take long to check, its a process of elimination ,

do you have a synergy box fitted ?

no synergy box
its box standard
its not pipes they all new silicone ones & egr buy pass fitted
today i put in some injector cleaner

generally funs sweeet @ 40mpg

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if that's the case .. but ..

it has a flat spot/ slight hesitation at light throttle

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could be just the way it is .. as standard ..
( unless it were better before .. and this 'hesitation' is something new you've noticed )

or could be the maf is a bit out of spec ..
( any idea when .. or if that was changed ?? )

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mine was like that untill i installed a 'synergy 2a' ..

before the synergy fittment ..
i'd done the egr 'delete' .. installed silicone hoses ..
fitted the bmw crank vent gizmo a short time after the synergy ..
as far as i know the original maf was o.k. at 37k when i bought it ..
but it might also been a bit out of spec .. i don't know .. was running fine ..
( have since changed it to a pierburg maf )

try moving the go-pedal at a quicker rate ..
as the ecu takes note of both go-pedal position ..
as well as .. the rate at which it is pressed down ..

if your confident the injectors are fine ..
and all other bits of the fuel system are o.k. ..
and the injector harness and its connectors are in good order ..
install synergy 2a and a pierburg maf .. or get a remap done 'n test the current maf ..
either way .. go-pedal response will improve over 'standard' ..

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btw : only thing i don't recall is if the flat-spot-on-lite-throttle was there Before i deleted the egr unit
as i did the egr mod within maybe two weeks of ownership .. feb.2012 ..
.. mine seemed almost to lose a bit of power .. the adding a bit more pedal would pass that 'spot' ..
( what i'm sayin .. it Might be the egr delete unit that causes a slight flat spot .. but Don't know for Sure )
was minimal though .. easy to adapt to ..