Misfire and P0302 - Not Coilpack or plugs, HELP.

[hatchn]

Hi all,

I have a 996 cab 3.6 (2002) and a few weeks ago we were away on vacation and I got the engine check light come up at idle and in very slow traffic.

It flashes at tick over when it's warm (off the "choke") and also when driving very very slowly, at speed it is solid.

I took it to my mechanic today and he has said the errors are P0300 (misfire) and P0302 (cylinder 2) nothing else at all.

So, coil pack or plugs you would think, but they have both been swapped out twice and no better.

The Mechanic has also used his box of tricks to switch off each injector in turn and the engine gets lumpier as each injector is switched of except when switching off cylinder 2 injector. When he switches off injector two it has no effect at all.

So we are now thinking it's the injector in cylinder 2.

He said this is very unusual so before we go down the road of ordering and fitting a new injector to cylinder 2 can anyone suggest anything else to try?

Cheers,

Nick

Edited September 27, 2010 by hatchn

[Loren]

Easy enough to swap injector from one cylinder to another and see if the problem follows the injector.

[hatchn]

Thanks for that Loren, my mechanic seemed to think the labour to swap injectors round would be about the same as buying a new one and just fitting it anyway.

Other than the injector can you think of anything else to try?

Cheers,

Nick

[wvicary]

Doesn't anybody use noid lights to test the DME side of the injector? You can also measure the injector for an open circuit.

[hatchn]

** UPDATE **

Had a compression test this morning and that all came back 100% OK so that is a huge relief.

We are still looking at the injector being the issues and will run some more tests on that.

Another suggestion is that the one of the two cam sensor may have gone on that side but I would have thought that all cylinders on that side would then have an issues and not just one but apparently this is not always the case.

Anymore suggestions would be greatly received and I'll keep you posted on progress,

Cheers,

Nick

[02tx996cab]

Depending on where you filled up during vacation, you may have gotten iffy gasoline which has partially gacked up an injector. Try running the car "briskly" on a tankful of top tier fuel (Chevron, Shell or Exxon's premium grades) plus a bottle of Techron or other injector/fuel system cleaner. That'll clean up your injectors and fuel system and may clear the problem.

I had a very similar problem after a 4000 mile road trip which required a few fill-ups with off-brand fuels. After my mechanic verified there was nothing seriously wrong, I did the above treatment cycle a couple of times; my CEL cleared after a few driving cycles and has stayed clear ever since.

Good luck.

Edited September 29, 2010 by 02tx996cab

[hatchn]

** UPDATE **

Swapped injectors and still no better.

Porsche technical now saying replace the cam sensors.

Cheers,

Nick

[Ahsai]

Have they checked the DME side of both the coil and the fuel injector connection/power for cylinder #2?

** UPDATE **

Swapped injectors and still no better.

Porsche technical now saying replace the cam sensors.

Cheers,

Nick