Not trying to hi-jack the thread from the original poster but, I'm having a similar issue. Overheats at longer idles ( stoplights, drive thru, traffic.......) while in motion it stays nice and cool. I noticed someone ask how the engine bay looked. Mine is as he was asking, not the cleanest, oil on the valve cover. Last year I did replace the plastic tank, cap, thermostat, water pump, rad hoses, and temp sensor to get rid of a worse overheating issue. Now its drive able but can't idle long. Its an 88 with the 4.0, only running a mechanical fan with no shroud (bought that way). I plan on grabbing an electric fan this weekend from a upull and throwing in it but is there more I should look for or grab to try and assist with temps while there?