I bought a 97 XJ6 last winter and it has been a fantastic car, however, just recently its been giving me some trouble. When its cold, the car will run great for about 30 min to an hour.

However, after getting warm, for some odd reason the idle goes haywire, and it won't stay running. Every time you try to restart, it'll run but the time it runs just gets shorter and shorter. Also, the transmission light on the dashboard turns on. These are the OBD 2 codes that are currently reading

P0443
P1447
P0732
P0727

Now I should add that I just recently changed the transmission filter and upgraded the fluid to the most recent Dexron. I also have a new purge valve coming because one of the hose inlets cracked. Would just the broken purge valve create this problem or do I have other issues going on here?

 

Your Car is most likely going into "limp Mode" this happens to my car in very hot conditions only though I'm not sure how to fix it other than don't drive a 20 year old electronic engine in hot weather lol. When you restart does it ride rough or is it the same as normal? if it only happens when your engine gets to operating temperature try removing the thermostat and drive it to see if it happens again.

 

I'd suggest checking out the temperature sensor. The ECU uses a different signal than the dash temp gauge so what you see on the dash may not be what the ECU thinks.

If your code reader can display Live Data, check what temperature the ECU thinks it at as the car warms up.

Alternatively, connect a multimeter to the temp sensor and measure the resistance as the car warms up. You should see gradual and progressive change. Keep measuring all the way to fully hot. These sensors can develop a dead spot at a particular temperature, or just die completely over a certain temperature.

Also, check the connector to the temp sensor is sound.

 

Your transmission requires dexron 3. If you refilled with dexron 6, which has a lower initial viscosity, that may be the problem.