For the past couple of days my 09 XF non-S/C has been throwing engine codes upon cold morning start-up. It only happens when I start it first thing in the morning at the within the first minute of starting the engine. Both times the codes have been the same:

P0301
P0302
P0055
Manufacturer control code

So a misfire on 1 and 3 and H02S Heater Resistance (Bank 1, sensor 3). After this initial occurrence the car drives perfectly and doesn't throw any more engine codes.

Has anyone ever experienced this before? Thanks in advance for the help.

 

Haven't experienced that on either of the 4.2l Jags I had, but what's your mileage? Time for new plugs, perhaps, and they can certainly be getting more fouled with the misfires. On the other hand, maybe it just isn't adjusted to the colder start-up temps yet.

 

Thanks for the response. Mileage is 83k km (52k miles)

The last two days have been the coldest startups I've experienced with the xf since buying it last January. Last winter it was housed in a parking garage overnight. So I don't really have any other cold morning startups to compare it to.

I'll keep an eye on it over the next few days

 

On the S-Type - largely the same car - the O2 sensors must be good or you can get other codes so I think I'd fix that first. After that, if the P030x codes come back it's going to be coils, most likely, not plugs. Plugs are good for 100K miles and although theoretically you could have a bad one, having two so soon is very unlikely. If you do get the P030x back, check for contaminants (damp, oil etc) in the plug wells as the coils are damaged that way most often.

 

Could potentially have been a case of bad gas or maybe high ethanol content in my tank. I was running the car on less than 20% of a tank of gas for a couple days. I filled up last night and this morning the conditions were even colder and no check engine light.

I'll continue to keep an eye on it. Thanks for everyones replys.

 

My misfire was supposedly due to dirty injectors or at least that what the dealer told me when I had misfires in my SC 4.2 (@ 35k miles). They said it's very common with the 4.2L motor. They suggested running BG44k injector cleaner every so often. I thought they were full of crap but I run about 1 can of cleaner through the car about every 2 months and I haven't had a misfire since. I haven't heard anyone else with the 4.2L SC or NA reporting this issue so I'm not sure what to think.

The O2 sensor light is odd... If you could track it down to the connector maybe some electrical grease on the pins in the connector would help. Maybe there is condensation in the connector.

 

Can't hurt to run the Barry Grant stuff. It is high quality.
But I will argue that the 4.2L SC Engine is NOT prone to injector clogging or other problems.

My 2005 STR at 96K miles has all the original coils, plugs and injectors and it still runs strong with no miss fires or check engine lights.
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thanks for the suggestion.....I'll grab a bottle of BG44k to be on the safe side

 

Won't be plugs, they're iridium and very long service life: 100,000 mikes or more, nobody really knows. Iridium is VERY hard and electrode erosion is minimal.

Try Shell V power 91 which has no ethanol according to Shell.

Some winter gas has a lot of ethanol in Canada.

Also, the heater on the O2 sensor may fail or the wiring may fail. O2 sensors are very durable and reliable but the wiring may not be.

 

+1 on the plugs being good - changed mine at 100K and I reckon they could've gone longer. I'll be very glad if I get to 200K!

 

Certainly sounds like it could have been a gas issue, and it seems like a good idea to run some high quality injector cleaner through the system to try to clear any fouling. Of course if there was a bad gas situation, that can easily cause both injector and spark plug fouling, but it seems like you've found the likely cause.

 

Same conditions this morning, no check engine light.

I'll chalk this up to a case of bad gas or higher ethanol content at the tail end of the tank of gas. Thanks everyone. I'll grab some BG44K today and run it through the system.

FYI I always use Costco gas that has 10% ethanol so I'll probably consider switching to Shell 91 to avoid any fouling in the future.