I have just done my regular oil change, but when I started the engine I noticed a strange noise from the rear of the engine.

I can only describe it as a slight wheezing, or puffing noise, but that may be a little ambiguous? It is also quite apparent when switching off!

Any ideas?

is there any signs of fuel around the injectors,the 1.4 are well known for the injector seals leaking ans could be the culprit of the noise

This is what I was thinking.

It certainly sounds as though one of the injectors is leaking, but I just cannot see if there is any oil, or diesel deposits around any of them.

I have tried to feel if there is any air escaping from them also, but still no joy.

Am tempted to purchase a set of seals and have a go at replacing them, if it isn't too complicated?

The symptoms you describe sound like injector seals, or possibly inlet manifold o-rings blowing.

Have a look for carbon deposits around each injector. (take the airbox off for a better look) The injector seals can be a real pain to change, the hardest part is getting the injectors out of the head. If the seals have been blowing for a long time it makes it even worse.

The inlet manifold o-rings are easier to change, basically rocker cover off and the o-rings are underneath 4 of them. These would have to be changed when doing the injector seals as the rocker cover has to come off to get access to the injectors. Space is pretty tight as well.

Yes I tend to agree.

I have removed the air filter housing to take a better look and have found deposits around number 1 cylinder (looking from front of car - first cylinder on left), but cannot really identify whether its oil that has run down from the filler, or carbon/diesel deposits?

It is still running fine for the moment, but did intend to get some seals and attempt the job in the very near future. If however, removing the injectors is a major problem, I may take it to my local garage to sort out?

I have removed number one injector and found it was leaking very badly.

After carefully removing all the carbon deposits from around the injector unit I have fitted a new set of seals and have reassembled the parts.

On starting up however, the engine is running very 'Lumpy' and is now misfiring. The Powertrain warning light is also now illuminated on the dashboard and there is little or no power.

I was extremely careful when handling and cleaning the injector, but can on;ly assume this is where the problem lies.

Any further advice would be appreciated!

Just to update you all.

After leaving the vehicle for 24 hours it started at first attempt, without misfiring or running 'Lumpy'. The Powertrain light extinguished but the Engine Management light then came on.

I took it into my local Auto Electrics shop who reset the ECU, at a fair old price I must say for 5 minutes work, but BINGO, all is now sorted.

No idea why the engine was running 'Lumpy' and misfiring in the first place? And I certainly have no idea why it would start and run fine after leaving the vehicle stand?

[b]Its a FORD CONUNDRUM !!![/b]