Help required for a newbie !!!

Hello all.

I am new on here so just want to say hello, and ask for help and advise.
I have a 300 tdi, 1995 that has been runnig fine until today.
Without warning, it developed what can only be described as a miss fire. Foot to the floor to get anywhere and blowing smoke out under load.
This gradually got better on the journey home. Driving it now, it seems fine.
However, there seem to be a noise resonating into the air box that can only be described as a chugging noise, it is quite loud.
The cooling system isnt pressurising, there is no water loss, there is no water in the oil. No oil has been burnt since I last topped it up which was 3 weeks ago.
If you pull the rocker cover cap off while the engine is running, there is no heavy breathing or signs of water.
If you crack each of the injectors off individually, the engine note drops evenly on all 4 cylinders and there is a good pulse of fuel at the injectors.
I have had the inlet pipe off to the turbo and had a look inside. The impellar is all intact and there isnt any real play to indicate a turbo failure.
BUT, the noise persists. From inside the car, it does actually sound like a miss fire while stationary and driving, but the power is all there.
The EGR has already been blanked off, but apart from that, the engine is totally stock.
Can anyone help........................

Im no expert but chugging noise could be air blowing back up air intake.Think the head might have to come off for further investigation.

The annoying thing is, it appears to be running fine, its not getting hot, not using oil, nothing !!!

Jake...

Hi mate

Have you checked all the air inlet pipes?
I had a similar problem that turned out to be the 90 degree bent pipe had collapsed inside and wasn't letting the air in.

Hiya,

Which pipe are you talking about ?
Its real annoying as the engine appears to be performing ok, but you just know that there is something not right !!!
It isnt giving any of the usual symptoms of a cracked head etc. Cylinder balance is even, no pressurising etc.

Jake...

Mine was fine to drive, then I'd come to a junction after about 15 mins of it running. I then pulled off round the round about, and it just crawled along bellowing out smoke. Pulled over and switched it off for five minutes and then it was fine until i got to work 10 mins later. The pipe was obviously relaxing and allowing enough air into the engine. Does this sound like your symptoms?

If you follow the pipe back from the airbox, there's a straight pipe and then a 90 degree bent pipe joined onto it (from what i can remember), well it was that one that was the problem. But i'd check all of the air inlet pipes.
Hope this helps!!!

Think he means 90 degree turbo hose connected to turbo charger