Constant misfires in cyl 2 but only in neutral

**A4ORCE07** · 10-25-2008 08:35 AM

Under load the car drives fine, no power loss. However, when i am at idle it is rough and I get a flashing cel. Put the car in gear, drive and everything is fine again. I know i'm running on only 3 cylinders whenever i'm not in gear. Did a diagnostic and it shows repeated misfires, like 200 in 30 seconds.
So what I did was:
1) bought new coilpacks and switched them - did nothing
2) switched plugs - fine there
3) checked compression- good compression
4) moved around fuel injectors - nada
5) checked for stuck secondary air pump - normal
6) replaced wires to harness cause some of the wire had melted away from engine heat- zippo

What gives? the only thing I noticed was the the actual harness for cyl 2 had misaligned teeth connecting to the coilpack. All the other were the same. Could this be the issue? Anyone know if you can buy a harness for just 1 cylinder instead of all 4?

**B6driver** · 10-25-2008 12:00 PM

fuel pump/filter?

**diagnosticator** · 10-25-2008 02:00 PM

Are you saying the wiring harness connector on cp 2 does not key into the cp mating side of the connector properly? You can buy a replacement cp wiring harness connector housing from the dealer, then carefully move each wire terminal from the old to the new connector housing.

**dirtybrd** · 10-25-2008 02:22 PM

Leave the car in neutral and while its running try moving the connector for that CP and see if it misses.

**A4ORCE07** · 10-25-2008 03:40 PM

Originally Posted by diagnosticator

Are you saying the wiring harness connector on cp 2 does not key into the cp mating side of the connector properly? You can buy a replacement cp wiring harness connector housing from the dealer, then carefully move each wire terminal from the old to the new connector housing.

Yes. At least I think/hope thats the problem. The teeth on cp2 harness do plug into the coilpack but I don't know if its making a good connection. It is wierd though that its only happening in neutral and not in drive. Dealer told me that I have to buy all new harnesses and wires (not sold individually). I also took it to my mechanic and he wanted me to leave the car with him so he can take the engine apart. I don't want to pay for unnecessary labor. The only other thing I can think of is software (APR) or some affect of running race gas for the last 6 months.

**dirtybrd** · 10-25-2008 04:46 PM

Did you try my idea? Can you post a pic. of the connector issue? The part that goes into the coilpack.

**diagnosticator** · 10-25-2008 05:56 PM

Originally Posted by A4ORCE07

Yes. At least I think/hope thats the problem. The teeth on cp2 harness do plug into the coilpack but I don't know if its making a good connection. It is wierd though that its only happening in neutral and not in drive. Dealer told me that I have to buy all new harnesses and wires (not sold individually). I also took it to my mechanic and he wanted me to leave the car with him so he can take the engine apart. I don't want to pay for unnecessary labor. The only other thing I can think of is software (APR) or some affect of running race gas for the last 6 months.

Try the connector wiggle test like "dirtybrd" suggested, with the engine idling. If there is a loose terminal contact causing the symptom, that test may confirm the location/situation*.
One explanation I have experienced before, for the gear related, as engaged or not symptom conditon, is that the vibration intensity and position of the engine is a bit differrent in drive compared to in neutral, and this sometimes will effect the pull on the harness and connectors a little bit, enough to cause the loose connection to be intermittent in gear and OK in neutral. (This happend on a Ford ignition distributer wiring hareness connector, in the case I found to occur before)

The dealer is wrong, about buying replacent connector housings, you can get each wiring harness connector/wire terminal housing by itself, and you can also buy the matching wire terminals pre-crimped onto "repair wires" with an identical wire terminal on each end of the 6" repair wire.

*(Sometimes, the contact fingers of the wire terminal get bent out of proper alignment, and can't maintain a tight electrical connection with the mating terminal pin on adjacent half of the connector/device.)