2004 Cayenne S Hesitation

[SWFLHOMES]

When I start up cold in the morning everyhting runs fine. Once it warms up (within about 15 minutes) it starts hesitating and running rough at idal. It smells like it's running rich and my milage drops by 4 mpg! I have about 73,000 mile so I figured I would change out the coils and the spark plugs. Nothing changed. Any ideas???

[RFM]

Read out the fault codes, there are certainly codes in the DME memory.

[SWFLHOMES]

RFM,

Thanks always for your help!

P0300 - Random Cylinder misfire

P0303 - #3 misfire

P0352 - Coil B Primary / Secondary circuit misfunction

P0302 - #4 Cylinder misfire

This problem came on instantly. I just changed the coils and plugs. It is hesitating and running rich.

[wvicary]

Be sure to check the connection on the ignition coils that they are securely attached and for any failed fuses in both fuse blocks.

[SWFLHOMES]

Checked the fuses. No problem there. I guess I can pull all of the covers and check the connections. I was carefull to make sue they were in all the way but a second look wouldn't hurt. Do you know the cylinder order?

[RFM]

Weird, are you sure about the correct coil and connector install, cylinder 3 and 4 are not very easily accessible (V8).

Came the problem suddenly (spontaneously) or after a modification, work on the car or something ? The relationship between engine running time/engine temp. and the showed codes looks strange to me, sure there are no further codes in the memory and no CEL ? The actual values should provide more clarity to the problem, in some cases the throttle body was the culprit. Clear the codes, do a test drive and check the codes again with a PIWIS if possible.

[SWFLHOMES]

RFM,

Are Cyl 3 & 4 on the left facing the engine closest to the firewall? If anything, I'll pull them and re-check them.

[RFM]

Cylinder 4 is closest to the firewall, cylinder bank 1, right side of the car (with the oil filler cap). Success.

[SWFLHOMES]

RFM,

I pulled bank 1 cover and the torsion mount (twice). The first time I noticed that cyliner 2 or 3 (the one under the mount) wiring was pulled out. I plugged it back in and it ran perfect! I put it back together and fired it up... more hesitation! What had happened was I routed the wire for the coil UNDER the mount. Once I tightened the mount it pulled out the coil wire. After re-routing the wire ABOVE the mount, no more problems. Thanks again for everyones time and advice. I would have not been happy if the plug/coil job didn't fix the hesitation.

[RFM]

Next time it will be no longer a problem, i'm pretty sure on that. Glad it is fixed cheap.