Low idle and misfire

I have a 03 plate TD5 MANUAL when you first start it dosnt matter if it's cold or warm (worse cold) but fires up runs like it's going to die revs pick up but if you press the throttle it will rev lazy and all of a sudden pick up and rev freely, I have just fitted a regal sport exhaust And new turbo cartridge I started it with the down pipe off and could here the misfire really bad then picked up and ran ok but slight misfire under throttle but it has had new harness and injector seals how common are they for the injectors to fail them selfs ??

What about the glow plugs?, some td5's can be very sensitive to glow plugs operation even if it's not cold outside cos theyr's post-heat activity after start up is important

Never thought about that, are you referring to the glow plugs them selfs or the glow plug relay ?

I refer to glow plugs operation entirely which means to check theyr's resistance, across the terminal and earth it must be 0.9 Ohm then measure voltage in one of the connectors immediately after ignition is on or engine just started

That sounds fine so long as its not number 5 thats misfiring.

What's the problem if it's number 5 ?

Just answered my own question ha only 4 heater plugs the old L series used to be like that 4 cylinders with 3 heaters

Not many people know that, I remember one parts seller on ebay selling td5 glow plugs in sets of 5
My D3 has a little flutter on cold start no matter what the weather is, pretty certain its not glow plugs as its the same in winter, one of the injectors is close to its max trim limit so this is most likely the problem, I even have the new injector just cant be arsed!

All heater plugs and relay working fine as should so what's next lads and lasses ?

Cheap laser temp probe pointed at the ex manifold at each port, coldest one will most likely be your issue, if it only does it from cold the testing may take some time!
I assume you have checked the fuel pressure at the head? 4 bar from memory.

Next time before you first start it in the morning run a 5 throttle purge sequence on it... if it will start and run fine after that without the described symptom replace the air bleed valve in the rear wheel side port of the fuel filter housing(WJN500110), if you replace it run a purge as well after that

Dosnt make a difference purging the system starts abit better but it still holds back on reving if you go to drive off it's like the power isn't there then boom it's the alway about 30 seconds after starting dosnt matter if it's from cold or warm start just get the real low idle from cold start and the misfire worse when cold, it has done this since I got it I have a egr bypass, decat, no centre box waste gate mod, snorkel I have slightly larger wheels which I no makes the pulling away abit more harder ( insa turbo supa tracks ) how can I check the fuel pressure?

I have noticed today I doubled checked the fuel pump in tank and found one of the high pressure pipes has been cut and replaced with rubber running under the floor

That'll be someone replacing the "Green Pipe" because of a leak.
Griff

That's the one need to replace and see if it fixes it