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Well that didn’t take long. Got my STR back from the shop and it took all of 3 days before it decided to act poorly again. Also getting restricted preformance light too.
Will get it home and throw a new coil at it in the morning. Hoping that’s the problem. Spark plugs are basically new so I don’t imagine that’s the problem. Engine air filter is also new. 
Got my STR back from the shop and it took all of 3 days before it decided to act poorly again...
Please throw us poor dogs a bone. Why was your car in the shop? Routine maintenance? Trouble? If trouble, are the current symptoms new or same as before? What work was performed?
Originally Posted by Mclovin22
Will get it home and throw a new coil at it in the morning.
Rather than new, I'd suggest swapping a known-good coil from another cylinder. See if the problem follows the suspect coil. Sadly, there are plenty of questionable parts out there. It can be a troubleshooting nightmare to install a part bad from stock.
Not sure what's happening with the P1797. Note it is flagged as a hard fault. The P0301 is a lower priority pending code. Misfire monitoring is prone to false alarms, so generally the computer wants to see it on successive trips before alerting the driver. A pending misfire code won't trigger restricted performance mode. That must be coming from P1797. That's a communication failure with the TCM and potentially more worrisome.
That's why I was asking about the recent work and any previous symptoms. There is a connector inside the transmission well-known to cause trouble, but I'm not well versed on that. Maybe somebody else can chime in with more details and what the symptoms might be. It would be a red flag if the shop had been working inside the transmission and this new fault appeared.
Please throw us poor dogs a bone. Why was your car in the shop? Routine maintenance? Trouble? If trouble, are the current symptoms new or same as before? What work was performed?
Rather than new, I'd suggest swapping a known-good coil from another cylinder. See if the problem follows the suspect coil. Sadly, there are plenty of questionable parts out there. It can be a troubleshooting nightmare to install a part bad from stock.
Not sure what's happening with the P1797. Note it is flagged as a hard fault. The P0301 is a lower priority pending code. Misfire monitoring is prone to false alarms, so generally the computer wants to see it on successive trips before alerting the driver. A pending misfire code won't trigger restricted performance mode. That must be coming from P1797. That's a communication failure with the TCM and potentially more worrisome.
That's why I was asking about the recent work and any previous symptoms. There is a connector inside the transmission well-known to cause trouble, but I'm not well versed on that. Maybe somebody else can chime in with more details and what the symptoms might be. It would be a red flag if the shop had been working inside the transmission and this new fault appeared.
More than happy to throw a bone, in-fact I’ll throw a whole steak. So my 06 STR was in the shop for a month due to my own incompetence. I thankfully have an agreed value policy on my Jag through American National “I pay around 412 for 6 months”. I’ve got the car appraised and valued at $20k. It came in handy when the A/C condenser, Fan Shroud, radiator as well as trans cooler lines got damaged due to bad advice from a friend as to where to jack it. Jack failed & slipped causing several thousand in damage. Not sure if you’ve looked recently but the cost of a new fan shroud for a 4.2S/C V8 is over $1k alone just for the part. I got the car back on 11/15/23 and was just fine till the night of the 18th.
Update as far as today, I swapped coils and the misfire followed as is the case with bad coils usually. I then went and got a new coil and the misfire seemingly was then at only number 7 as of this morning. I was going to then buy a new coil for #7 “I got duralast but will order oem this coming week”. Never did get that far though as a friend invited me out, and I decided to take a break from working on the Jag. Below I’ve included the screen shots of the code from this morning showing the cylinder 7 misfire, as well as tonight when I brought home a new Jaguar companion for the S Type. The codes that showed up when I fired the S Type to move the XJS into the garage we’re the P0300,P0301, P0302, P0316, & P0307 as pictured below.
My plan for tomorrow “Monday 11/19” is to return the “Duralast” ignition coil, and order a full set of replacement oem “Denso” coils that are on the car. It wouldn’t surprise me if some need replacing anyway so I could knock it out as a measure of preventative maintenance. If anyone has other recommendations for ignition coils let me know as I’m open to ideas/suggestions. Last 2 pictures are the hickey that got my STR in the shop in the first place.
Code from this morning S Types New soon to be running companion
Working from potentially faulty memory, but I think somebody here recently had a similar problem and he tracked it down to damaged wiring across the front of the engine compartment. That came to mind when you mentioned the physical damage in the same area, but the fault looks to be gone at the moment.
Working from potentially faulty memory, but I think somebody here recently had a similar problem and he tracked it down to damaged wiring across the front of the engine compartment. That came to mind when you mentioned the physical damage in the same area, but the fault looks to be gone at the moment.
Well it certainly looks like the P1797 cleared itself. I’ll check the harness for damage too but I’d think if it was damaged it would’ve thrown these codes right after I got the car not several days later.
Misfire Cyl 1 06 STR
