P2096, P2098, P1646, P1647 codes

[Jazzwineman]

2005 S-Type 3.0 120K.

I have been struggling over the years with a P1646, 1647 that would ONLY occur at idle and ONLY in the summer during high heat days in Dallas. Most of the time, I wold be driving on the expressway and then come to idle at a stop light for a couple of minutes and I guess that was generating the higher heat. This has never occurred when I am actually driving the car and only at idle. Most of the year- zero problems. A Jag tech i know from 2000 miles awy was good enough to suggest that I must have some resistance in one of the circuits and that will higher heat the resistance goes up. That makes good and common sense. Usually it I got a code with CEL, the next morning I could go drive the car around, make several stops and usually on about the third or forth stop the CEL goes away. If I have a pending code, it would go away when I turned the car on in the morning.

Now out of the blue in the last week I am getting code P2096 and P2098 on top of and apparently before the P1646 and P1647, which are circuit failures or sensor failure in either or(I assume both) the upstream and downstream O2 sensors.

The upstream are 2 years old with about 13k on them and the downstream are about 5 years old, with 25-30 K on them. Previously when I had changed the upstream on 2 occasions, it did nothing to impact the 1646 or 1647 codes. It just seems to me that replacing all the sensors is a waste of money, but worth a try if it makes sense.

I have both the ISCAN and SDD and none of the fuel trims or voltages of the sensors are out of whack or range.

I had pending codes last night, erased them and this morning did the 15 minutes of idle after it was to running temp and I had pending 2096 and 2098. I then took a short drive and I now have pending all 4. I guess I could always have developed some exhaust leak, but this is a garaged car and I don't drive more than about 6500 miles a year and there is no rust as if I were in a very wet or snowy area and I can hear nothing to indicate a leak noise.

I know the testing on the 1646 and 1647, but it appears on the surface to be daunting. I am assuming the the 2096 and 2098 are an extension of the problem that was only 1646 and 1647 before. I have also reset with the battery to let it relearn, but that appears to be of no help.

Has anyone had this experience with all 4 codes or any thoughts, suggestions or ideas as to what to do now. It does not affect the drivability of the car and my inspection is not due for 7 months. It does not have a rough idle and I have no hesitations. Could this be slightly caused by the fact that I do lots of short trips 80% of the time?

I am open to all suggestions except to take it to the dealer as I know the ways on a situation of this nature they would try to exact money from me in their typical unethical ways.

Thanks for any help in advance.

Tom in Dallas /Plano

05 S-Type 3.0 120K