Constant misfire cyl #1

Hi all,

I have finished my s52 swap into a 318ti. Both are model year 97s if it matters. The car has rebuilt 24# injectors from Bfc classifieds,m50 manifold with Eric's kit, dinan bbtb, asc delete, new spark plugs (NGK single prong)

I am having a constant misfire on cylinder #1. I receive a code for that and also a hard code that is always on, o2 sensor probe 2.



I have 3 grounds (2straps, 1 brown wire) connected. The seller I purchased the motor from provided good comp #s with +/-5 psi across the 6 cylinders.



I have swapped the coils and the misfire stays on cylinder 1. The car runs rough (sounds like a Subaru).





Next step for me is to swap the injectors around to see if the misfire follows.



One other thing to note is the car ran fine when I first flashed stock manual m3 software on it. The flash completed, I turned the car off, then on, and it ran perfect. Then the misfire came back after a minute or so.



Does anyone else have any other suggestions on how I should go about diagnosing the problem?

I'd appreciate any help.

Constant misfire cyl #1