Thankfully I haven't had a problem with my car since the new transmission was installed but of course a new issue was bound to crop up. I got a CEL just after starting while driving through my parking garage at work. p0300/p0305. I cleared it right away but I could tell it wasn't running right at low rpm/idle and low load.
First I swapped the plug/injector between cyl. 5 and 6, but on Durametric, the counter still incremented misfires on 5 just as it was before.
The valve actuators are new, the brackets are not broken, and in the past when I've had this low-load misfire issue it was an injector. I posted a lengthy thread here about it a couple years ago.
I'm running EPL's 72lb injectors and for some time I've been considering replacing them with 60lb injectors and going with a Cobb setup.
My question is, has anyone else had similar issues with the injectors I'm using? If so, was it the injector itself, or the adapter that is used to permit it to connect to the Porsche harness.
One more thing I recall is that the #2 and #5 injectors have to sit at an angle to permit clearance of the connector adapter.
For now logic tells me to just pick up another injector from EPL and hope that cures the problem.
Under full load there is no issue. It just isn't idling right and accumulates a tremendous number of misfires under light throttle. I posted this to show what is happening.

 

No suggestions? I probably didn't do a good enough job explaining what is going on on that video. I just pointed my go-pro at the durametric screen showing actual values for misfires on all cylinders while driving around and parking and revving the engine. Number 5 is at the bottom. As you can see, under load it doesn't accumulate misfires and sometimes when idling it will be fine. It was raining yesterday so I couldn't give it much throttle in any gear for fear of changing direction unintentionally.
One other clue is that as the misfires on cyl.5 are much worse after the engine is run hard for a while and on very hot days. Let me reiterate, they don't occur at high load/rpm, but after pushing the car for a while, the misfires tend to accumulate at a much faster rate.
Since no one has any suggestions I'm going to order a spare injector and new harness adapter and replace #5. If that doesn't do it I will do a compression check.
I don't think the internals have a problem because the issue is intermittent. I sure hope it's not a burned valve or intake lifter variocam issue (which it better not be since my lifters only have 2K miles on them).

 

I don't think either your injector or adapter are at fault. You'd be seeing a PO155 code and PO300. I had a similar issue and it turned out to be the !@#$%^ adapter!

I also have an occasional misfire on cylinder # 2. What seems to help, is smaller spark plug gap .032" on a Bosh FR 6 LDC. I also tested the continuity on a bunch of coils, old and new with no obvious results. What I did see though is that there is a dab of conductive grease on the connection between the coil and the tube which fits on the spark plug. I swapped an older tube with more grease onto a newer coil and it seems to help. I also reset the fuel trims by disconnecting the battery and that allowed me to pass emission here in CA with no CEL to be recorded at the DMV.

I am now thinking of the fuel pump/hoses since misfires can happen when low on gas, says Mr. Porsche. On 1 cylinder, all of them, who knows...

My 2 cents.

 

I run FR6LDC plugs and use the stock gap which is what my tuner recommends. The adapters that snap into the injectors have been known to cause problems over time and fortunately I have a spare. This weekend I'm going to take out injector 5, clean it and the spare adapter I have thoroughly and put it back together, and install the assembly into cylinder 6, moving the injector/adapter in cylinder 6 to 5. If the problem is gone, chances are it was the adapter. If the problem moves to 6, this points to a flakey injector. If nothing changes...compression test.
In any case, when you get to the point where the fuel rail is removed you can see a lot more and anything else that may be failing could reveal itself.

 

Well stock gap is not good. Im running the same issue as you and my gap was supposed to be at .24 right now im at .30

 

I called EPL to order an injector and they suggested first cleaning the connector/adapter because over time the metal tends to corrode between the adapter and the injector. I took out the fuel rail, removed the adapters and cleaned both sides with an automotive electronics spray cleaner. Then I applied dielectric grease on all contacts on both sides (facing connector in harness and facing connector on injector)
After reassembling everything the misfires were gone. EPL says this is a common problem when using adapters between injectors and harnesses so if you are having intermittent misfires and it isn't corrected by replacing plugs/coils if you run connector adapters on your injectors, you may want to check their contacts.
I'm going to check the connector that goes to the fuel pump also since many people have posted photos of burned up connectors in this area and adding dielectric grease and cleaning the contacts seems like a great idea.

 

Glad it was an easy solution. Thankfully, sometimes it ends up being something basic.

 

It was a very basic issue; that I'll agree with. Easy solution, not so much. Changing the MAF sensor - that's an easy solution. Removing the passenger side fuel injectors with the engine in the car is a PITA!

 

I've had one of the 72 lb bosch injector go bad before and in another case the harness loosen up over time. Ended going with the siemens 60lbs injector and never looked back again.

 

I had the same situation on bank 1 two years ago, moved the problem injector (1) to cyl. 3, and in that case the injector turned out to be bad. After a month, the problem reappeared on cyl 3. In that case I had to buy a replacement.
This time because I cleaned and applied dielectric grease on all points of contact I'm hoping the problem does not reappear.
When the issue occurred two years ago I just swapped injectors with their adapters whole.

Let me ask you, did EPL re-tune your car for the smaller injectors or did you move to another tuner? I've been thinking for my power level slightly smaller injectors would provide better idle and light-throttle drivability.

 

I ended up going to a GIAC tune with the siemens injector.
Lol, I may have 6 bosch injector in my junk box from a couple of years ago with the harness adapter. Never like the harness adapter part ..maybe mental..
I also went with the hitachi maf at the same time.
I don't think idle is any better. I still have a warm idle hunting issue on mine sometimes dipping 150-175 rpm . (people say vacuum leak, I've chased and found none)

 

I think I'm having a mental problem with the harness adapters at this point too. The frustrating part is that before getting the the injectors, you still have to go through all the obvious things like plugs, coils, cam solenoids / mounts all for nothing only to find that a two dollar harness adapter is the problem. The ones that came with my injector kit have a very cheap feel to them and I don't like how they only clip on one side of the injector. I wish there was an injector they could use that was a direct fit into the Porsche harness.

 

abi=out all you can do is cut the plugs off the harness and hard wire the new plugs for the injectors your using

 

Why don't you guys use injectors without adapters? I'm using Bosch injectors that are identical visually to OEM but the jets are resized internally by Bosch for more flow. = OEM reliability