Hi, if you have a 99 GMC Suburban that kills during warm weather don't spend thousands on repairs. Mine did this intermittantly, particularly in warm weather with the AC running, until I killed and a mechanic saw me. He stopped and asked the following: Is that a 1999? Yes Does it kills for no reason? Yes Is it worse when the weather is warm, like above 85 degrees? Yes Does your engine gauge read hot? No Here's the problem. He popped the hood pulled the top off the fuse box that is located on the drivers side and told me to let it cool down and go to the auto parts store and buy a new relay for the fuel pump and the AC. I did this and haven't had a problem since. Unfortunately, I had already dumped abotu $2500 into a new cat converter, fuel pump, fuel filter (twice), negative battery cable, four new 02 sensors, etc... My biggest beef is the dealer hit me for $2000 of that and he should have known better. I replaced the fule pump relay and the AC relay for under $20. Grrrrrr!