If these problems could be fixed affordably this could be the best car I've ever owned. Yesterday on the highway it got between 38-42 MPG which is extremely excellent fuel mileage for such a big car. So if I can get it fixed it's worth keeping. It has 127,XXX miles on it. The biggest problem is that it runs absolutely fine on cool days below 73 degrees F. But any warmer than that and/or when the car is driven more than 20 minutes non stop then the car stalls and sometimes when I go to start it the engine knocks like crazy and is stuck at 500 RPM. Then 30 seconds or so it usually comes out of it and runs and sounds normal again. If I continue to drive in stop and go traffic on a hot day it may continue to stall and may or may not knock loudly. This happens when the temp gauge is reaching is in between the ¼ mark and the ½ mark. I have noticed if I turn on the heat full blast that reduces the engine temp which temporarily relieves the problem. The other problem is my A/C. When I bought the car 2 years ago it worked really well. Now it doesn't work at all. I've tried adding R-134A and then sometimes it would work temporally but now that doesn't seem to do the job. Does anybody know what could be causing these problems or have had these problems with there LHS and had them fixed? Any good information would be very much appreciated. Thanks!