Engine Trouble. Would love some help. AOS?

[thstone]

This can often be a spark plug or coil issue.

Swap the coil packs from cyls 3 and 5 with the coil packs on the other side (4,6). Then see if you get a CEL for misfires on cyls 4 and 6. If so, replace those two coil packs. If the misfire stays with cyls 3 and 5, replace the spark plugs.

The reason that misfires are damaging to the cats is that when a misfire occurs, there is incomplete burning of the fuel and there is only so much fuel (or hydrocarbon) that a cat can take before it is permanently damaged. You should be fine running the engine to diagnose and repair the misfire but don't ignore the problem and continue to drive it while misfiring for a long period.

[EJ_2001_986_S]

Thanks, I'll give that a try and see what happens. I may just go ahead and invest in new coils and plugs all the way around since the car literally turned over 60,000 miles as I drove away from the Autozone after having the codes checked.

[Nine8Six]

Originally Posted by EJ_2001_986_S

Thanks, I'll give that a try and see what happens. I may just go ahead and invest in new coils and plugs all the way around since the car literally turned over 60,000 miles as I drove away from the Autozone after having the codes checked.

Had those codes and all that associated Harley Davidson idle thing as well.... and done this on my 986 at 50k (this spring). Mind you mine is an old car and see the road once a month only (if lucky!).

1. New battery
2. Coil packs
3. Sparkplugs
4. MAF (genuine, not the ebay test-failed unit)
5. ultrasonic cleaning of injectors
6. TB cleaned ultrasonic also
7. AOS
8. Mobil 1 Oil (every 2,000km!) 1,500miles?
9. All filters
10. Coolant change
11. ATF and filter change
10. New car freshener (lavender)

I liked it soooo bloody much I took off for a 700km round trip in the mountains of Zhejiang province. Non stop. No music. Alone (don't tell)

Buy "lavender". You'll see!

[EJ_2001_986_S]

I'm going to try plugs and coils this week and see what happens.

I was all ready to do an oil change and swap sway bar end links yesterday before this happened, so I'll get in there and do everything at once now.

Thanks for the tip on the lavender. I'll have to be sure to explain that to the wife though. Coming home smelling like lavender might make a misfire on the Boxster the least of my worries.