how can I increase the ilde when the air conditioner compressor is running? Below 1,000 rpm, the compressor vibrates a lot and make a bad sound. Above 1,000 everything is ok... new compressor. I am aware how to adjust the idle without the a/c running... by turning the factory-sealed adjustment screw near the air intake, intake manafold... Thanks! Andrew

Howdy all, I have a 1998 GMC Jimmy, 2WD, 4.3 V6, with an automatic transmission and roughly 150k miles. This evening it started to overheat and the "Check Gages" light came on, and the temp gage eventually pegged out at 260 before I could get it parked. I had to drive about 2 miles before I could get it somewhere safe to park. I tried running the heat, in hopes of pulling some heat off the heater core to keep it a little cooler, but only ambient temperature air was coming out of the vents. Just before I shut it down I could hear some rattling, and about the same time the temp gage pegged out the other way and the "Service Engine Soon" light came on. Luckily I had parked at a Wal-Mart and was able to get some water. I was inside about 30-40 minutes letting it cool down. I then checked the oil and it was fine, no sign of water. The coolant overflow reservoir was nearly full with really foul, dark looking stuff. After I cracked the cap on the radiator, all that fluid was pulled out of the overflow, but there was some obvious grit (for lack of a better descriptor) left inside the overflow tank. The engine started fine and ran ok while I was putting some water in the radiator. I got about a half gallon in it and then checked the temp - it was at about 215-220 with very little upward movement. So, now I'm a little worried since I had to drive it that far to get it parked, and I hope there's been no damage. Does anyone have an idea of where to begin checking this thing out? Thanks in advance!