Re: Explorer stalls?
You'll have to narrow down the 'whine' you hear. It could be the rear diff, front diff (if 4x4), or even the most common area - the serp belt tension pulley itself. There are ways to test, even a slightly GOOD mechanic should be able to find the source of the sound rather easily.
As for the erratic RPMs, it'll take some troubleshooting to get it sorted out if there are no engine codes. I'd start with replacing a few usual sensors such as the IAC (idle speed controller) and TPS (throttle position sensor) as they are the most likely ones to be causing the problem. Both are located on the throttle body. The IAC can be cleaned if you're careful not to move the plunger in the sensor. Spray it down with carb cleaner, wipe dry and reinstall. The TPS cannot be cleaned successfully as it's sealed. Both sensors will run $40-60 depending on where you get it from. Aftermarket sensors tend to be less expensive than dealer parts, so shop around!
Other folks will offer their suggestions shortly!
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!