1999 996 Rough run

[jose]

Hello,

Having rough runing. Durametrics scan this codes. Seems the problem can be cylinder #1 misfire. What can be the possibles issues? Spark plugs? Coil #1? Anything else?

 

Thanks in advance

[JFP in PA]

The P0130 and 0150 codes are both potential wiring harness issues (shorts or low voltage signals).  If the car was in my shop, I would make note of the codes and then clear them all, and then take the car out for a run to see what comes back.  It is unusual for both O2 sensors ahead of the main cat to develop problems simultaneously, so it could be a harness problem rather than the sensors themselves.  If the 0130 and 0150 codes return, I would check the sensors themselves for the correct voltages; if they check out, I would start looking at the harness for shorts or other issues.  The misfires could be connected to the sensor issues, or a coil or plug problem. 

[jose]

Thanks for reply, 

I cleared the codes and reappeared again. What mean the P1313? Can a Single coil problem cause the simultaneous O2 sensor bilateral?

[JFP in PA]

13 hours ago, jose said:

Thanks for reply, 

I cleared the codes and reappeared again. What mean the P1313? Can a Single coil problem cause the simultaneous O2 sensor bilateral?

Not really, the misfire may just be a separate issue, but a misfire on one bank cannot cause an O2 issue on the other bank.

[jose]

Thanks for reply, 

I cleared the codes and reappeared again. What mean the P1313? Can a Single coil problem cause the simultaneous O2 sensor bilateral?

 

I have an update pictures of cylinder #1 coil. Coolant reservoir hose might be the culprit.

Edited July 9 by jose

[JFP in PA]

Coil housing looks like it is cracked, if it is, can it and replace it.

[jose]

I cannot understand why this hose was there. My last mechanic replaced the waterpump and coolant cap not too many miles ago.

I made a purchased same brand "beru". I will attempt to do it my self and reroute the hose. I'll rescan and report results.

[jose]

Update. Coil replaced. Same codes. Passenger side axsust seems misfiring. Driver side is okay.

Edited July 24 by jose

[JFP in PA]

Did you clear all the codes after changing the coil?  If not, do so now, and then wait to see what returns,

 

There are only a few reasons why a cylinder misfires: Coil is bad, plug is bad, coil is not getting power or firing signal from the DME.

[jose]

Yes, I clear the codes after replacing it.

[JFP in PA]

Then you need to pull the plug on that cylinder and check it out and then start running electrical diagnostics on the cylinder in question; is the coil seeing full voltage, are there any shorts or voltage drops in the coil harness wires, is the coil seeing a firing signal, etc.

[jose]

I have durametrics with very limited knowledge. Basically reading the codes. But with specific instructions I can follow and post results.

Edited July 24 by jose

[jose]

I had this actual values. Anything wrong here? 

Edited July 24 by jose

[jose]

MAF was unplugged. Put it back. CEL came back.

Edited July 24 by jose

[JFP in PA]

It is extremely hard to read your screen shots due to the reflections, but from what I can see, the O2 sensors look like they are performing correctly.

 

As for the misfires, you are going to need much more than the diagnostic software to trace it.  The coil packs on these engines have multiple leads running to them, which would require a wiring diagram for you decipher which is which.  One wire carries a 12V signal on it at all times the engine is running, another of the wires runs all the way to the DME where the DME creates a momentary ground at the moment the coil should fire; you would need a digital multimeter to check these harness wires for the correct voltage on the power lead, and a ground signal on the wiring going to the DME only when the DME creates it; if shows a ground at any other time, there is a short to ground between the coil and the DME causing it to constantly fire; if there is no short to ground, the DME MUST create a momentary ground at the correct crank rotation point for the coil to fire the plug. If that is not happening, either the wire is cut before it reaches the DME, or the DME is acting up.

 

If all this is out of your depth, I would suggest taking the car to a qualified Porsche shop for them to have a look at it.

[JFP in PA]

9 minutes ago, jose said:

Must add an important point. I Replaced the coil and erased code retest it but in the process I cleaned the MAF sensor and forgot connect it back. Again, erase it took those screenshot. No check engine light yet. But engine feels rough "idle".

If you ran it without the MAF connected, the engine should idle fine.

[jose]

An update. Summary insert MAF, cleared CEL, started vehicle idle. Codes are reduced to three codes.

[JFP in PA]

You still have the misfire, and it is impacting the O2 sensor on the same bank.

[jose]

Will replace  O2 sensor as last check before taking it to the mechanic.