Ford Repair: Overheating/Jerky acceleration, blown head gasket, synthetic oil change

Question
I have a problem with my 1999 Ford Explorer 4.0L SOHC. For the past couple days, it has started to accelerate very jerky at time along with now getting to the "3/4" mark on the temperature gauge right in between middle and overheating. Today, it got as close as its been on overheating. If you gave it a percent on the temperature gauge it would have been 90. When I turned the A/C off today, it went back to normal temp but then went back up to the 3/4 mark again closer to HOT. All fans seem to be working good. Nothing seems out of ordinary under the hood. Radiator hoses feel soft and pliable. There is plenty of coolant in reservoir and I just had a synthetic oil change yesterday. Please help me out if you can.

Answer
You should have it checked for a stuck thermostat, or blown head gasket. A bad thermostat itself will not cause the jerking problem, so that makes me think you may possibly have a bad head gasket or something like that where coolant is getting into a cylinder. Do you notice any smoke or steam coming out the exhaust? Feel both the radiator hoses, if the top is hot and the bottom much cooler it is probably a thermostat.