1986 Ford Bronco Not sure

Other Category problem
1986 Ford Bronco V6 Four Wheel Drive Automatic 160000 miles

I have a 1986 Ford Bronco II with the 2.9 V6 and an automatic trans. I got it really cheap and it had very little rust for its age especially here in ohio.I replaced the brake booster the drivers window and put in a radio. I also did a general tune-up to it, plugs wires and cap and rotor, also changed the oil and filter. I drove it to work, about 15 miles on way and after about a week it started leaking trans fluid, a few days later it was running out the front of the trans. Took it to a shop and they replace the front bushing and the seal and put in a new converter. Started driving to work again and I noticed that after warming up, about 3 miles of driving it would start acting up. It would stumble and sputter and begin to lose power, if I would give it gas it would downshift and run ok again until it reached cruising speed and it would do it all over again. Then I noticed that when I came to a stop sign and sat there for 10 seconds or so that when I took off the problem would disappear. This became routine, it would start acting up and I would pull over and stop and then continue and it would be ok. Then one day I stopped for coffee and turned it off, when I started it up and started to drive the problem had returned, stopped and sat and then it would go away when I started driving again. Have been to several sites and there is a variety of answers to consider. The main one was a vacuum leak this is a list of the things that I have done since and the results.1. Checked all of the vacuum hoses and replaced 2 of them also the one going to the vacuum modulator on the trans had a slight amount of fluid in it so I replaced the modulator too. 2. I put in a new thermostat (seemed to take forever for gauge to warm up on a cold morning). Test drove it and it would do the same thing. 3. Replaced the following; ignition module, temprature sensor, throttle position sensor, ground wire from battery. Also replaced the gas tank due to a leak from rust also sprayed carb cleaner into the throttle to clean it up. Also adjusted a noisy lifter. Test drove it again and at the 3 mile mark it would do the same thing except now it would die when the problem started. Stopping now has no effect on it and the problem is now all the time. The car will start up even while I am coasting if I put it in nuetral. As soon as I put it in drive it does the same old thing. It runs fine if I just let it sit in the driveway but as soon as I drive it and put it under a load it does it again. Any help would be greatly appreciated as this is now nickel and diming me to death.I don't really like the car and don't want to get rid of it. Would like to put in a 4.0 in the distant future and give it to one of my grandsons. Thanx again and have a nice day. Mike