i have a 4.6 4x4 STX, and at 21,000 its having problems now, last week i heard a loud pop in my front driver hub area, its only done it once, so i cant' pinpoint it, and when i turned a corner on pavement, i had a loud "chunk" come from the rear end, im guessing the axle but i could be wrong, and lately it has been starting harder and harder, this morning i had to crank it over 3 different times for it to start, then when it takes off it hesitates, and when i push on the gas after i started it, black smoke was coming out the tailpipes,(i have true dual exhaust) and when i go to move in Drive, i push the gas down in first gear its responsing time is not that good, but i put it in second, and its like it is missing in the lower RPM's. i dont have a tach so i can't tell you what rpm's. but its hesitant, and it runs really rough now, it shakes my rearview mirrors and my passenger seat. dont get me wrong, i really didnt realize this would be a huge paragraph, cuz i love my truck, i just wanted to know if im the only person with these symptoms. thanks for your help in advance

 

Might have a plug/coil problem. Get her into the shop ASAP. Also, you can have a tach; hold down the trip odometer reset button while you start the engine, this will get the display into test mode. press the button a few times to cycle through the displays, then you will eventually get to a digital Tachometer.