Hello Jaguar Forum. Let me start with some info. The car is a 2000 S-type 4.0 with 123600 miles. I purchased the car as a backup get me to work vehicle mainly because I have always wanted a Jaguar. The car had a slight misfire at idle when I bought it. After researching on this forum I changed the plugs and all eight COPs. I checked for oil or coolant in plug wells and found nothing. At that time the car had two codes p0304 and p0307. None pending. Also the gas smelled old so I drained the fuel as best as possible and replaced the fuel filter along with general maintence. The fuel pump was changed by the previous owner about 6 months before I got the car. I also changed all four O2 sensors. Drove the car about 800 miles with no issues. Then 2 days ago I filled gas (premium) and went to work. Temperatures dropped to about -20 F. Started car as usual. Starts right up but as soon as the idle comes down the engine quits. Pending codes showed slow O2 sensor warm up on bank 1 sensor 2 and misfire on cylinder 4. I held the idle up until car warmed up and the misfire went away and the car idled fine. Same thing this morning and tonight. Same two codes although the misfire caused a CEL and was confirmed the other is still pending. I tried to listen for a hiss when the engine quit but heard nothing. Checked the airbox and intake elbow for leaks. Did a harness shake here and there to see if a wire went bad or loose connection.Nothing. I got the fuel trims tonight when car was at 180 F at idle STFT1 -2.3% STFT2 -.8% and then at 2500 rpms. STFT1 -1.6 and STFT2 -4.7. Any thoughts are greatly appreciated!!!

 

As far as the P0304 goes - you could have a "dud" coil, especially if they are an aftermarket brand.

Personally I only use Motorcraft or Jaguar OEM coils.

Move the coil to another cylinder to see if the code "follows".

Also, make sure the electrical connectors on each coil and each fuel injector are on nice and snug. (A loose electrical connector at the fuel injector can set a misfire code and cause your engine to miss and cut out)

Check each one at a time. Some are difficult to see but can be easily disturbed when changing coils and since you had all 8 changes you should check each electrical connector starting w/ cyl #4

Hope this helps..

 

Need trims including LTFTs, hot engine, at idle & rev to about 2500

An air leak too small to hear will make a car cut out. Trims will tell if you have one or you can smoke test but it's not easy compared to reading trims.

It's of course critical that the coils & O2s are all working & proper types.

 

Jagv8. I took the car for a longer drive and then idled for about 2 minutes before noting the fuel trims. Coolant temp was 203. STFT1 -3.1% STFT2 6.3% LTFT1 -29.7% LTFT2 -12.5% at idle and at 2500rpms STFT1-6.3% STFT210.2% LTFT1 -17.2% and LTFT2 -3.9%. I hope this is better info for you. Per the recommendations I found on this forum prior to servicing the car I purchased Motorcraft COPs and plugs. The o2 sensors were OEM as well.
abonano I moved the coil to a different cylinder but the issue stays with #4. The injector connector does not look good however as the clip that holds it is broke out. I didn't notice that when I did coils. I am going to replace the pigtail but I think you were right on the money with the connector issue. Thanks folks!!

 

Huge -ve trims means it's subtracting LOTS of fuel (that's the opposite of what would happen with an air leak).

I can't see why you don''t have rich code(s) like P0172 / P0175.

More than one thing could be the cause so grab the codes PDF / JTIS and read under those codes

 

Good find on the connector but please post back when you fix the problem.

We all learn from your repairs.
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The plastic retaining tab breaking on the fuel injector connector is quite common. If you push the connector down it should be fine. It's a tight fit.

For those injector connectors (under the intake manifold) use a flat blade screwdriver to seat the connector to the injector (if the tab is broken/missing)

 

abonano, thanks for the heads up. I went ahead and soldered in a new pigtail because after noticing the tab was missing i removed the connector by basically touching it lightly. The bottom side was broken out. I checked the other connectors which are fine. I cleared the confirmed p0304 and drove the car home so far so good no codes. However there is still something not quite right. Starts and stays running now but sounds wrong to me and seems to smell rich until the car warms up. Perhaps I have fixed one issue and it will help me find the deeper issue!
jagv8, I read through the codes p0172/175 per your advice. I am checking through the possible causes and will update with any new information. Thanks folks

 

Today I believe the mystery for has been either been solved or at least the majority of the issue taken care of. After the connector issue I found on the injector I decided to do a very careful inspection of electrical connectors on the engine. I can tell that at one point the valve covers and intake have been removed as evident by the marks on the bolts and the missing or not functioning "tree" plastic holders on the harnesses. I found three additional injector connectors that were missing tabs but still seated fairly well and one additional that the connector body was cracked and the pins loose inside. I replaced those. The big surprise was when I wiggled the harness lead to the AAC valve located on the throttle body assembly and it fell off!!!! Obviously some intermittent contact going on there. Luckily this was a type of connector that I carry on my service truck and promptly removed the pins in order and replaced the connector body. The old connector was not completely broken but the locking tab did not seem to "click" or seat the way I like. After completing my inspection I started the car and noticed a definite improvement in idle and no more off smell in the exhaust. Ran out time to do much more than go for a quick ten mile cruise. No pun intended but the car seemed to just purr! thank you again forum members for your time and consideration. The tech guides and other technical info here is just awesome!!

 

Sounds great! Let's hope that's it fixed.