Hi guys,

I drive a Freelander 2003 td4 BMW engine. It had around 200 000 km but that is something everybody in my country is illegally changing before selling so I can't really be sure. I have a really weird issue with loss of power and EML light coming on.
This has been happening for 3 months now. I have tried several different mechanics (including the official dealership) and had no luck so far. I would like to keep it short for you guys but my symptoms have been changing over time so I am afraid I will miss some vital information. Because of that, I am afraid I will have to describe the last 3 months of my life I have searched this forum and many others and nowhere have I found something so specific.
Disclaimer: I will try to translate everything properly to English as in my country most car parts have German-borrowed words. Also if my English is bad please bear with me.

It all started in July. I was on vacation in a different country and my car started losing power uphill. When it did it had dark smoke from the exhaust and the EML light was on. Took it to a mechanic and he said that the code showed injector number 3 being bad. He sent it to injector servicing. They returned it without finding any issues. The mechanic put it back and everything was fine. He told me not to worry as he tested the car and he believes everything is fine and maybe there was some dirt on the connector or something similar. I tested it myself and it was fine for the next 50 km.

On the way home, it happened again on the freeway. I have managed to drive it to the next mechanic back home. He said the pipe from the intercooler to the engine wasn't properly fastened. He did so and everything is fine. I decided to test it with him as this time it sounded a bit weird. We drove uphill in 5th gear at 100 km/hour and had no issues.

After that, I drove it for like 100 km or so and it happened again. This time symptoms changed because there was no more black smoke and also loss of power wasn't only uphill. Also while out of gear just testing the gas pedal the error would be there while pressing the gas. When I release the pedal it would disappear while the revs are getting down until it goes completely to idle then it would appear again. Also, the sound while on idle is like a tank or a tractor (TAKA TAKA TAKA TAKA). I drove it to the mechanic again. This time he said my vacuum pipe that turns on the turbine was disconnected. Once he connected it all was fine. Again I tested it uphill and drove fast and with a heavy load. Everything works perfectly.

After another 100 km or so it all happened again. Brought it to the same mechanic and he changed the 3rd injector for a new one. After another 50-100 km it happened again. This time he said that he has no idea what is happening. The moment he clears the error using diagnostics everything starts working fine.
Since mechanics are obviously really bad in my area I decided to somehow get it to the official dealership (didn't do it yet since its 200 km from my home). Driving there it started shutting down as a new symptom. After resting for 5-10 minutes it would turn on and drive again. Somehow I got it there. There they told me the same thing about clearing the error. Also, they tested it and exactly after 50-100 km it would all happen again. In the end, they told me its too old to be worked on and that I should abandon it. I was hoping that was not the case.

I started searching all over the country for somebody that knows what is happening. One mechanic said we should replace the fuel pressure regulator as that's why it's shutting down. After changing that it no longer shut down but soon same old issue happened again.

Now I tried to find just a good mechanic no matter what kind of cars he is used to fixing. Just that he is good. Found one 100 km from my home. All my contacts tell me it's the best one they knew. He changed the wiring towards the injectors and it started working again. I left it in the city with my friend to drive it to work for 5 days just to be sure. Then I drove it home for 100 km. And one day later it all happened again.

Now I tried searching the internet and found that the MAF sensor is a common power loss issue. As soon as I removed the air hoses to get to it, error disappeared. I removed it to try it out like that and the error was gone until I got on an uphill. Also, I noticed when running the engine without the top cover that oil was spraying from one of the bolt holes (bolts from the cover). This wasn't happening before and not sure is it related to my issue or if it's a new issue.

At this moment I am lost. Don't know what to do. Should I bring it again to a mechanic, or maybe light it on fire or drive it into a lake
Any help would be appreciated.

Thanks!