Hi, I have a misfire when starting from cold, its intermittent and only lasts for 15-30 seconds. If standing outside the car there is a smell of Petrol from the exhaust. Jaguar have had the car for over a week now and typically the fault has not appeared. They are telling my there are NO fault codes and the sensor are all reading in bounds. It appears to happen when its been cold over night, and it only happens on the first start of the day.
When it happens, the engine misfire is a hunting type of misfire.

Has anyone seen this type of random fault?


Many thanks

 

Just once this occurred on my 4.2. Until the fault occurs in the shop or a code gets recorded I'd ignore this problem.

 

Unfortunately the warranty is just about to end :-(
Otherwise I would completely agree

Thanks

 

Re checking my service records I note that my dealer updated the engine software to correct this fault on my car. There's a specific reflash for hard starting. There's been no recurrence since that reflash was done.

 

Thanks for the ideas, I also noticed I was only getting 24mpg the other day on a run, so having left the car with jag dealer for 2 weeks and they found nothing wrong. I thought it time to look myself now its out of warranty, sure enough cheched for fault codes, nothing, so I cleaned the MAF sensor next to the air cleaner, guess what, 31mpg on a run now, only time will tell if the misfire has gone and a very cold morning. I do not understand why the MOT 2 weeks ago didn't show rich running

 

Not sure the degree of misfire you are experiencing. On my new 5.0 XF I noticed a slight roughness at idle on startup when we purchased the car. It lasted only a few seconds. Have seen it again once or twice since but, we have hardly driven the car since the purchase.

I am not worried about it because at startup the fuel/air mixture may be quite different from when it is already warmed up or in the process of warming up fully. If it clears after 15 seconds, I have no issues with it.

Albert