Since I bought my Turbo it will randomly misfire at steady state speed about once every 10 times I drive it. The CEL blinks between 2 and 10 seconds before going off. When I plug in the durametric it show cylinder 1 and 3 misfires and nothing else. The plugs and coils have all been changed and the problem persists. It doesn't cause any drivability issues and never happens under boost or anything over steady state cruising throttle.

Anyone had this issue before?

oh and my frunk latch stopped popping today. Won't pop with button on door sill or with remote. I do hear whirring noise from latch when I press the release on the fob, but hood doesn't pop. Going to have to dig for the manual pull and see what's what.

 

Maybe try pressing down on the hood while someone else activates it? Or alternately try tugging, might just be stiff.

 

this is how much time i have on my hands LOL

the frunk latch has a compressed air mechanism that makes it "pop" the frunk. they go bad, and yours probably has. its not an expensive part and may also be a 996/986 shared part. i got one on ebay a year ago, no issues since.

you'll need to dig under the passenger wheel well liner to locate the emergency catch wire, and once you replace the frunk latch mechanism, i would ( and did ) re-route the wire so its sits under the seam where the headlamp meets the rubber liner. it'll only be barely visible to you if staring down into the recess, but it'll be instantly available to you with a needelnose plier the next time you have a dead battery or whatever and need to pull the latch if the fob wont do it. this is the part you'll need
the manual release wire is inside the right hand fender - inner fender liner must be removed - then the actuator is located inside the front trunk under the fabrics, front right hand corner.

but i forgot to mention/add on the misfire issue that if you have ensured your coils are new and none are hairline cracked? in injectors-fuel filter dirty possible.. agreed. try a bottle of techron! ya just never know. good luck.

 

Tried both...no luck

 

Thanks again! I'm game to try anything that's cheap. Can't hurt!

 

cant blame ya a bit. mine was used from ebay also..similarly priced to the one you located. works like a charm good luck.

 

The misfire problem can arise from one or more bad injectors.

This gets a bit tricky. While in your engine's case the misfires are 1 and 3 the bad injector -- if it is a bad injector -- may be at cylinder #2. It stops working. The O2 sensor reading shows a lean condition. The DME adds fuel. Since the #2 injector isn't working or isn't working very well the DME adds more fuel until the 2 healthy cylinders start to rich misfire. (That is what the flashing CEL means.)

Like plugs and coils I'm reluctant to just whip out an injector and start swapping these around. The less handling these receive along with the fuel lines and wiring harness the better I like it.

OTOH, I'm reluctant to just advise you to replace the #2 injector let alone replace all 3 injectors on that bank.

I'm also reluctant to suggest you data log various engine telemetry during this misfiring as I do not like to drive a misfiring engine for fear of causing collateral damage.

If you data log you might see the short term fuel trim an the #1 cylinder bank go very positive as the DME attempts to add fuel to address the lean condition I spoke of above.

There can be other causes of the misfires. Are there any pending error codes? In some cases the VarioCam Plus system can act up -- cam timing is not what it should be -- and as a result the DME will note a change in the O2 sensor reading on the affected bank. It will adjust fueling to that bank to try to get the reading it wants and the techs tell me that in some cases the adjustment goes so far the engine will develop a misfire.

Another problem is the variable lift feature acts up and one or more intake lifters fail to switch to low lift from high lift or vice versa when commanded by the DME.

The factory Porsche Turbo manual has a section on troubling shooting misfires that can arise from bad lifters. Too much to type in.

However, I have a PDF though that contains this info and can send it you via private email. If you are interested send me a private email and include an email address that can accept a 650Kb PDF file.

The techs tell me the hood latches can wear out. That you hear the mechanism attempting to work suggests this is the case.

But you'll have to dig into the latch mechanism to confirm what exactly is going on.

 

It's going to be pretty hard to catch the misfiring on a data log. It happens maybe once every 2-3 weeks for a few seconds.

There are no other pending error codes.

PDF on troubleshooting misfires would be great. I'll shoot you a PM.

 

what plugs did you use? denso Iridium?
is it tuned? by whom?
stock injectors?
time to do a good pressure test like this... trust me..


or

 

OEM plugs. Car is bone stock. I've been meaning to pick up one of your boost leak testers before I start modding it. I'll probably do that too. Thanks!

 

Hood latch actuator problem is fixed! The actuator had gotten lazy. I was able to open it with the button after letting it sit for a couple days without trying it. Then once it was open I actuated it with the glow in the dark emergency pull and each subsequent pull the actuator would pull less and less until it didn't pull at all. Installed the new one (super easy) and it works time after time without an issue.

It's a good thing I didn't need to use the manual pull cable. I found it routed to the inside edge of the passenger headlight. It would have been unreachable without pulling bumper off. I re-routed it under the headlight so I can grab it with needle nose pliers as some have recommended on here.

Tackling the random misfire next.

 

nice work! if only missifre diagnosis were as simple as the frunk. GL.