Can stretched timing chain cause an issue in only 1 cylinder

[Jayboy007]

I have a 2003 BMW 318i and had issue saying misfire on cylinder 4 only. Replaced spark plugs, coil packs, injectors tested and also compression tests done on cyclinders 1 and 4 and all came back fine. Swapped coil packs as well and issue stays on cylinder 4. Been told it could be caused by timing chain issue possibly being stretched. Is this likely to be causing only an issue with 1 cylinder rather than all of them. Any help appreciated. Thanks

[E-bmw]

No.

[Jayboy007]

Cheers. Any ideas on what could cause this sort of issue ?

[Touring442]

Could be an ECU with a blown injector driver. You'll buy an ECU kit (ECU, EWS box, key and ignition barrel) for well under £100 or a cheap 20 quid ECU and have the EWS deleted. You need to check for power at the injector though. It could be a badly worn valvetronic eccentric shaft; disconnect the sensor plug next to the oil filler cap. It's got two 10 mm bolts but you just pull the centre connector out. If it suddenly idles better, that's the problem. Replacing it is a bd of a job.