AUDI A3 140 TDI SERIOUS MISFIRE ! ANY SUGGESTIONS

my car recently developed a fault. it started a few weeks ago the car developed a short but severe misfire , then it went away and drove as normal ,suddenly the misfire returned very violent ,but with the feel that the car was drawing in air as sometimes the car would surge uncontrolably. the misfire then disappeared again.

i started to check things

i replaced the fuel pump in the tank , at this time i noticed the diesel was contaminated with oil

i replaced the fuel filter which seemed to cure the problem ,which i assumed it was because the filter was clogged .

i also replaced the tandem pump as this is the usual cause of oil in the fuel .

still the misfire remained

also replaced all the injector seals today was really hoping to cure the problem , started car fired up with the misfire no change.

really at a loss here , i dont mind spending money on the car to cure the fault but im getting no where fast and my wallet is getting lighter per day .

checked all the obvious with vagcom ,no injector faults ,fuel pressure at tandem pump checked .

swapped injector loom . no difference

engine jerks violently car ticks over at 1000-1200 rpm car cannot be reved smoothly try holding revs at 2000 rpm and they swing from 2000 to 3000 rpm

really dont want to take car to audi ,read a few stories of injector swaps ,cams followers etc and a bill of over £2500

i could buy a set of injectors only to find that its the cam ,whereas i could buy a complete engine for less money than a set of brand new injectors

to mean thats not pinpointing the fault thats just guessing and been lucky in the process.

has any one had the same sort of symptoms before and if so was there a definate cure ?

bump

this is information incase anyone in the future gets the same symptoms , the egr valve was broken , not the elctronic one but the old vacumn one , the end of the egr valve had broken off luckily it had fallen into the intercooler pipe , was diagnosed by blocking off the egr valve with a beer can . check this first ,will save you alot of time and expense , even though the injector seals had perished ,the egr failed at roughly the same time