Yesterday morning I suddenly got a Check Engine Light and Restricted Performance. Performance seemed fine until coasting at low rpms, at which point I could feel a slight misfire. Engine Link app tells me P0356: Ignition Coil "F" Primary/Secondary Circuit. "F" equals cylinder 6. I do a visual inspection...seems fine. I unplug the connector, clean with CRC cleaner, then reconnect. I clear the codes and everything seems fine now. We'll wait and see if it holds, but I guess sometimes all you need is a good reconnection.

 

Cool...keep us posted!

 

What I have done in the past is swap coils with another cylinder and if it does happen again, see if it follows the new cylinder its been swapped to. Then you know for fact it is a marginal coil issue and not wiring and you can safely replace the coil.

 

That was going to be my next step if the code returned, which it hasn't. So it looks like it might have just needed a re-seating.

 

So after getting codes for bad coils on #2,3,5&8, I used the old coils that I had replaced a few months ago when I bought a complete set. When I first replaced them, it was because I had a code for a bad coil on #2 so I assumed that one was bad but I did not marked that coil when I replaced the entire 8.


Today I went in and replaced 2,3,5&8 with the old ones. After starting the car up I got a code for #5. I am assuming that when I swapped out the new #5 with the old#5, it may have been the original bad coil. I pulled that out and put a different (old) coil in its place.

Started the car and got smooth acceleration. No codes. I took it for two test rides, one being up a long steep hill. So far, it is running the smoothest that I have experienced since owning the car.

I’m keeping my fingers crossed and I’ll be going over to the parts store with the (new) coils that are still under warranty.
Thanks for the posts and information. This site has really helped me out.
-Jim

 

I have been driving the XK8 on a regular basis since the weather has cooperated here in Western NY. I have gotten at least three error codes regarding “too rich” on both banks. Reviewed with my mechanic and he suggested another cleaning of the MAF sensor as well as the throttle body to ensure that nothing was hanging-up. This seemed to work well for about a week.
I got the error message again and this time the system shut down completely after a short drive. I did a hard re-set and everything came back.
Fast forward another week and today, I had another hard reset (no error codes) in order to return home after driving a few miles from home. The temperature is about 85 F today with 100% humidity (if that matters).
I am wondering how often a hard reset should be necessary and if it was indicative of a greater issue.

 

I believe there is a TSB warning about cleaning the throttle body, DON'T .

 

Never and the latter. Something serious is wrong and all you're doing is in effect ignoring it.

 

There are four connections on the coils which are for two separate coils.

When I had a bad coil I tested it with a multi meter and got continuity on

one pair and open circuit on the other pair.

If you suspect a coil then test it as above.

WRT the throttle body I have an used spare TB which I have cleaned.

I found that there was a coating about 1 cm wide where the butterfly is completely closed.

I think that this is the coating that should not be 'cleaned'.

So IMO cleaning is not a problem if removal of this coating is avoided.