I have a 2006 4.0L 4x4 Explorer that just lit up the "powertrain malfunction indicator" (wrench light) on the dash. I bought this vehicle over 4 years ago, and it has always hesitated when cold, (similar to a cold, carbureted engine for those of you who remember those...). It runs fine after. However, today after starting it cold, it hesitated, then shimmied, and then the powertrain malfunction indicator came on. I drove it 4 miles home, but it had shifting issues. I was planning on having it towed to the dealer, however, after reading another post, I see that it can be intermittent. Sure enough, I just went back out and started the vehicle - no light! Any ideas what this means???