I've had problems for maybe a year now with my C5. Firstly it started to vibrate a little so I cheched the engine mounts and found one that was completely worn. Replaced it last year. Vibration didn't stop though but only got worse! Then one day my friend called me that car suddenly sounds like a helicopter
But they had kept driving and suddenly it had stopped. Then little later I also got the so called helicopter sound and recognized it was surely running with 3 cylinders. I drove it like that for like 20 km and suddenly she run okay again. After that I put a couple of bottles of STP injector cleaner to the tank and continued driving and after that it hasn't run on 3 again. Oh, and sometimes the engine just suddenly shuts off. Happens especially with a cold motor. Starts fine after that every time. In a high acceleration it gives a little black cloud but not too bad I would say. And feels like it has about the expected 136 hp so no notable power loss.
I have checked the correction values for the injectors with a diagnostic tool, but the units are not familiar to me since they are reading ms?? I'll attach some pictures if anyone understands them. I also did a leak-off test and it wasn't too bad, all were pretty even, and the total amount wasn't too much either.
When listening with a screwdriver and earmuffs from the injection pipe connectors, cylinder number 4 sounds really different from the others. It's clattering badly compared to others.
So, my guess is that it's injector(s), because mechanical problems wouldn't just disappear suddenly (running on three a couple of times and then going back to normal suddenly).
Do the injectors need coding? It has Delphi injectors. And would you guys replace them all at once or just one? It has done about 410 000 km.
Here's the VIN to check for the injector coding: VF7**************[VIN obfuscated, can be read by forum staff]
