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Was running restricted performance multiple misfires I replace all spark plugs with iridium and new coils, clean the mass airflow sensor since then, the restricted performance has not came on however, the Miss is still there. I also did a smoke test on the vacuum system. No leaks any ideals?
I see one problem. Your scanner is giving you potentially misleading generic code definitions. Jaguar-specific definitions can be different than what your scanner tells you. Use the Jaguar OBD definitions available here:
For example, P1316 is a bad one. In Jagspeak, this means you've got a problem bad enough to overheat and melt the cats, an expensive proposition. This typically also flashes the Check Engine light to get your attention so you slow down and pull over. Your scanner is giving some vague (and wrong) code about the injector circuit.
P0307 and P0308 are accurate, meaning low power ("misfire") from cylinders 7 and 8.
[Soapbox mode] If the computer has set a misfire code, please be aware "misfire" wasn't the best terminology that could have been used. Misfire sounds like an ignition problem, at least to me, meaning the fuel and compression were there, but for whatever reason, the required spark was missing or weak. This might lead an aspiring mechanic to troubleshoot the daylights out of a perfectly good ignition system. I do not care to discuss how I know this.
In OBD-speak, misfire simply means one or more cylinders is putting out low power compared to the others. Pretty much anything affecting the output of a cylinder can set a misfire code. It can be low compression. It can be a valve not opening fully. It could be a clogged fuel injector. And yes, it could be an ignition problem, too, but don't overlook the other possibilities, too.
[Soapbox mode off/]
Codes P0354, P0356, and P0357 point to a problem with the ignition circuits on cylinders 4, 6, and 7 respectively. Bad coils? Possible, but it's really bad luck to have installed 3 bad coils. I'd suggest swapping the suspect coils to other known-good positions and see if the codes follow.
Your temperature gauge says it’s reading 75° F. And your cancel says your enclosed loop. I don’t think those to go together at 75F I think you’re still an open loop until you get up to like 180 or something so where is your coolant actually at 75F or is that wrong? If you coolant sensor is sending the wrong temperature to your PCM it’s going to throw off your mixture and timing and all sorts of different things which could result in you having a misfire so what temperature? What temp is your coolant at or how long had the car been running when you took those screenshots?
also, your idle is at 995, which is pretty high for idle it’s almost like a coldstart is it normally at 995 or does it usually run lower my car runs around 600 RPM after its warmed up
Are the P0354/6/7 codes new? Or did you have them before replacing the coils?
What's the recent history of the car? A low-mileage cream puff owned by a retired Jaguar engineer, driven only on sunny weekends? A abandoned derelict dragged out of a field? Something in between?
Are the P0354/6/7 codes new? Or did you have them before replacing the coils?
What's the recent history of the car? A low-mileage cream puff owned by a retired Jaguar engineer, driven only on sunny weekends? A abandoned derelict dragged out of a field? Something in between?
The car was running great with no issues until I stopped at the store when I came back out and started the Jag. I felt a very bad miss from there. It just got worse drove straight home.
Not even a mile away.
The car was running great with no issues until I stopped at the store when I came back out and started the Jag. I felt a very bad miss from there. It just got worse drove straight home.
Not even a mile away.
Just thinking out loud, but let's look at the probabilities of certain faults happening. Let's say a coil gave up the ghost at that moment. A single coil failure is not some remote possibility, and just so happened at start-up.
When this originally happened, did you pull any codes at the time? Wondering if you got any misfire codes such as P0301 - P0308, even if only pending. This would help isolate the source of the original fault.
Your fix was to replace the coils and plugs. My hunch (offered for free and worth every penny) is one of the new coils was bad from stock. This can be a troubleshooting nightmare, as nobody expects that:
Don't poo-poo the idea of parts bad from stock. I recently went through a headache of having a coil fail, with the misfortune of installing a new one (bad from stock) in the same position. Took lots of head-scratching and the precision use of foul language to figure that one out.
Now you've got the same basic problem continuing, perhaps originating from a different cylinder. But now you've got additional fault codes for electrical problems on the input to 4 random coils. Where did that come from all of a sudden?!!! If my line of thinking is correct (could there be any question?), one bad coil can be pulling down the voltage feeding the other 7. Due to normal manufacturing variations, 4 of them are dipping just low enough to trigger these uncommon codes. In one of my previous replies, I hadn't considered how an internally shorted coil could suck down the power supply to other coils.
The catalyst monitor problem? As JagV8 said, an ignition problem (with raw fuel reaching the cat) could be interfering with the equation. Computers can be very smart and very stupid at the same time, and can only respond as programmed. Sometimes you get a misleading response because the computer doesn't know how to process what it is seeing.
To summarize Proust (Bonus points if you know the obscure reference without searching), try swapping the suspect coils with known-good positions and see if the fault follows. I think #7 is the most likely culprit, as this cylinder is generating codes for both low power output (P0307) and P0357 (coil input circuit)
Just thinking out loud, but let's look at the probabilities of certain faults happening. Let's say a coil gave up the ghost at that moment. A single coil failure is not some remote possibility, and just so happened at start-up.
When this originally happened, did you pull any codes at the time? Wondering if you got any misfire codes such as P0301 - P0308, even if only pending. This would help isolate the source of the original fault.
Your fix was to replace the coils and plugs. My hunch (offered for free and worth every penny) is one of the new coils was bad from stock. This can be a troubleshooting nightmare, as nobody expects that:
Don't poo-poo the idea of parts bad from stock. I recently went through a headache of having a coil fail, with the misfortune of installing a new one (bad from stock) in the same position. Took lots of head-scratching and the precision use of foul language to figure that one out.
Now you've got the same basic problem continuing, perhaps originating from a different cylinder. But now you've got additional fault codes for electrical problems on the input to 4 random coils. Where did that come from all of a sudden?!!! If my line of thinking is correct (could there be any question?), one bad coil can be pulling down the voltage feeding the other 7. Due to normal manufacturing variations, 4 of them are dipping just low enough to trigger these uncommon codes. In one of my previous replies, I hadn't considered how an internally shorted coil could suck down the power supply to other coils.
The catalyst monitor problem? As JagV8 said, an ignition problem (with raw fuel reaching the cat) could be interfering with the equation. Computers can be very smart and very stupid at the same time, and can only respond as programmed. Sometimes you get a misleading response because the computer doesn't know how to process what it is seeing.
To summarize Proust (Bonus points if you know the obscure reference without searching), try swapping the suspect coils with known-good positions and see if the fault follows. I think #7 is the most likely culprit, as this cylinder is generating codes for both low power output (P0307) and P0357 (coil input circuit)
03-08-2023 | 07:25 AM
2006 jaguar S type 4.2 L misfire
