2010 VTi 95 running on 3 cylinders

So I've had this issue a couple of times over the past few years. First time I was just driving along the German Autobahn when suddenly "Engine Fault" appeared on the navigation screen. I pulled over, noticed a little rough idle, shut it off, waited for a few seconds, started it again and... problem solved? I drove it to the nearest gas station, called AA and had them check it. Other than low engine oil they could fine absolutely nothing wrong. No obvious codes in the ECU either. It still threw the "Engine fault" code but the AA guy removed it.

Fast forward a few months and it happened again, but a simple restart and the issue went away again. Made an appointment at the "local" citroen garage and had them check it. By the time they had time to pull codes, nothing was there anymore. Very odd. "Engine fault" disappeared from the startup sequence of noises and bleeps and bloops over the course of a week. They sent me on my way because other than randomly replacing parts without reason there was nothing they could do.

A few more months later it happened again. "Engine fault", shut off engine, restart engine, no more issue. But this time I drove it directly to the same garage and had them check it immediately. They haven't told me which codes it threw specifically but they did end up replacing all 4 spark plugs and 2 coils. That was Februari last year.

We're ~34K KM further down the road and yesterday morning the engine idled odd after a cold start. Didn't think much of it initially and proceeded out of the driveway. "Engine Fault". I thought I'd quickly pull the plugs to see if there was anything obvious but the only obvious thing was that none of my plug sockets fit. So I ordered one from Amazon. This morning I pulled the plugs and noticed that one plug had a bit of debris (non metallic, probably carbon) lodged in between the two electrodes. I thought I had finally found the culprit that had been plaguing me for the past 2 years. Since I had all new plugs (NGK Platinums) I put those in and thought for sure it'd be fixed now.

You may have seen this coming. It wasn't fixed. I tried revving it a bit to see if that'd fix it, but that didn't either. Silly me. Anyways, I'm now looking at my options. I can't drive it to the Citroen garage to have it checked simply because it's running on 3 cyls and the garage is ~30km from here (I live in a rural German village). I also don't have a way to read codes myself, I was about to buy a regular OBD2 reader yesterday but after reading about those things not being able to read half of the codes in these cars I removed it from my Amazon cart. I found an iCarsoft i970 that supposedly can read everything but that thing costs ~€120. I've seen the Lexia things on Amazon and eBay as well but I have no idea if those will work with my car since all the information I have seems to lean towards the pre-2010 C3's. Also, I don't have any Windows computers.

Right now I'm thinking it can be either one of two things, either an injector or (yet another) coil pack. If any of you have any bright ideas about how to determine which coil pack could potentially be faulty, I'd gladly hear about it. The plugs only have 3 connections, which I assume are +12V, ground and a pulse signal. As for the other end of the bang, I have no idea where the injectors on this engine are. Everything I find on the internet seems to refer to pre-2010 C3's and Haynes doesn't have a manual for this generation either.

TLDR;
- engine misfiring
- no obd2 reader
- replaced spark plugs
- still misfiring
- potentially coil pack, but how to determine which one?
- potentially injector, but where are they and how do I get them out / determine if they're bad?
- anyone know of a repair manual for a 2010 C3 (A51 iirc)?
- anyone know of an OBD2 scanner that'll give any sort of usable info in this situation?

c44 wrote: ↑Fri Oct 26, 2018 11:53 am They haven't told me which codes it threw specifically

Hi c44

You should read the codes yourself if they won't tell you what they are. Without the codes you can't do much diagnosis yourself.

Try one of these OBD2 scanners on the diag port to see what you actually have stored.