Slightly rough idle and hesitation.

[Rickmac]

Sorry my first post is a diagnosis question, but I do hope I can find some guidance.
So here's a little info about the car...
2010 135i m-sport 65,000 miles
Mods
Bms dci
Vrsf catless dp's
Cobb ap v2 stage 2 sport map

So about a week ago, I was running stage 1 aggressive (on stock downpipes) and when I opened the throttle, the engine hesitated, sputtered and threw the ses light. I checked the code and it was a misfire in bank 5.
I turned the car off, switched to stage 1 sport map, and cleared the codes. The code hasn't came back since then but at idle the engine will shake/sputter every 4-6 seconds or so and I still feel a slight hesitation while trying to go w.o.t.
The misfire scared me, so I changed all 6 plugs and swapped coil #5 with coil#2. Again no misfire or any codes, but problem persists.
My gut tells me it's the MAnifold absolute sensor, mainly because a few months ago an animal chewed through the map sensor wires which I had to strip and feed back onto the plug.. But it's been this wayear for months with no issues.

Any thoughts or recommendations on possible diagnosis or troubleshooting tips?

[ShocknAwe]

65k miles on a N54. When was the last time this car was walnut blasted?

For reference, mine has ~73k, had valves blasted at ~35k. I had the intake manifold off a week ago, it was HORRIBLE in there again, AND the level of carbon buildup was not consistent from cylinder to cylinder. Not the worst I've ever seen but it needs a cleaning.

[Rickmac]

Originally Posted by ShocknAwe

65k miles on a N54. When was the last time this car was walnut blasted?

For reference, mine has ~73k, had valves blasted at ~35k. I had the intake manifold off a week ago, it was HORRIBLE in there again, AND the level of carbon buildup was not consistent from cylinder to cylinder. Not the worst I've ever seen but it needs a cleaning.

Well I'm not 100% sure to be honest, I bought it used about 20,000 miles ago and I haven't had it done.. but I have been reading about that as well as a potential issue.

[ShocknAwe]

Originally Posted by Rickmac

Well I'm not 100% sure to be honest, I bought it used about 20,000 miles ago and I haven't had it done.. but I have been reading about that as well as a potential issue.

So maybe never then. If you can pull the IM back a hair you can take a peek at the Cyl 1 valves pretty easily. That will give you an idea of how dirty it is in there and if you want to have it blasted or DIY it. Easier to check if you have a scope to use.

[Rickmac]

Originally Posted by ShocknAwe

So maybe never then. If you can pull the IM back a hair you can take a peek at the Cyl 1 valves pretty easily. That will give you an idea of how dirty it is in there and if you want to have it blasted or DIY it. Easier to check if you have a scope to use.

I won't even bother looking. The more I look into it, it seems that most of these engines need it regularly every 30-40,000 miles... I'll probably just buy the blaster equipment and do it myself for the next time I need it as well. Hopefully this is the issue.

[135ivert]

Have you changed the coils? I just went and did all 6 (plus the PCV) and it's running & idling much smoother.

[Rickmac]

Originally Posted by 135ivert

Have you changed the coils? I just went and did all 6 (plus the PCV) and it's running & idling much smoother.

No I haven't yet. I just changed all 6 plugs and swapped coil 5 with coil 2 to see if the misfire changed cylinders if it came back. But it hasn't came back yet. That said, when I changed the plugs they looked pretty spent, and I doubt they had been changed since it rolled out of the factory, so I'm sure the coils are the same. They don't look that bad from what I can tell, but 65000 miles on a coil is a lot, so I'll probably change them for maintainance reasons.

In fact, I just installed the downpipes Tuesday and flashed to stage 2 sport map, and so far the issues are subsiding. I also used some fuel injector cleaner on Monday...

I think I'll just end up doing a walnut blasting and change the map sensor in the intake manifold, along the the map sensor on the charge pipe. They both have oil on them.

[Rickmac]

I just wanted to give an update in hopes for guidance.

I'm still having this rough idle and poor acceleration issue.
I just bought all the tools necessary to walnut blast my intake valves so that will be done tomorrow. But I'm starting to think these symptoms are due to a different issue. Mainly because the symptoms are getting worse and they seem extreme for just some carbon build up.
On idle, the car shakes and stutters every couple of seconds. While accelerating, I can feel the sudden loss and re-gain of power. A hesitation.
I also noticed a constant ticking noise which someone said could be bad injector (s).
And on top of all this I'm also hearing a rattle during low rpm/low gear acceleration, and at idle when I rev the engine. Which could be a failing wastegate.

Yet with all these symptoms I still have yet to get another code. I've actually tried by going wot on a cold engine, nothing..
I'm just praying I find the nastiest carbon build up in those intake valves. So I can clean the piss out of them and hopefully be sure that was the issue.
But if the problem persists, does anyone have any recommendations on a course of action? I'd like to avoid shops if possible. Im cheap and just simply don't trust them.
Basically I'm just looking for some tests I can do to help diagnos the issue.

I do have the cobb Accessport, so if I can monitor something on there that will tell me what's wrongoing, that would be great