Struggling D4D

[The Moz]

I own a 2008 Auris 2L D4D with 125,000 miles on. Bought it 3 years ago and been very reliable. However it has developed the following symptoms:

Very hard to start from cold, irrespective of air temperature, long cranking necessary then a spluttering start often with smoke. I now use Easy Start for cold starts.

hesitancy at low speeds, particularly when moving off (junctions etc) often followed by a surge and black smoke

Some loss of power, most noticeable at times climbing hills

Generally, once the engine is warm and at normal driving speeds the car seems to operate fine. I have noticed only a slight reduction in fuel economy but with using my motorbike much more in this season, that hasn't impacted too much.

An independent Toyota agency told me it is a faulty fuel injector and a friend who is a mechanic agreed saying the faulty one is leaking internally causing low fuel pressure for start-up and some over-fuelling causing the smoke and hesitancy. There are no warning lights showing.

What I'm asking is, apart from the expense of removing all injectors for pressure testing, is there another way to determine which injector is the faulty one? I electrically tested each injector and found their resistance measurements all identical and listening to them I hear each of them working, no misfiring that I detect.

I want to balance the economics of repairing a well liked and otherwise reliable but 12 year old car with possibly taking a hit on selling and replacing with a younger one.

Thank you

[Bhakti]

On diagnostic mechanic can see correction factor of every injector and determine faulty, 200 Euro cost repaired injector (like new).