TPS & interior lights question

[jerry]

Hi Guys,
Well it looks like I am now sufferring with the infamous TPS problems. For sometime now I have noticed the transmission hunting slightly when shifting into overdrive but did not think to much of it. This past week I was on the interstate traveling along in cruise control at 75 mph when all of a sudden the truck seemed to shift down a gear and slowed to about 60 the footfeed was on the floor and it acted like it was running on a governor the speed would not pickup over 65. I kicked it out of cruise and thinks returned to normal and ran fine again. Later I pulled out to pass a slower vehicle and was running about 80 when all of a sudden my speed dropped off and I couldn't go over 70 mph, I held it to the floor and it felt like it shifted gears, a puff of black smoke came out the exhaust and it ran right up to 85. The shifting has been erratic since. I put a volt meter on the middle wire on the TPS, at idle it reads exactly 1 volt at wot it reads 2.9 volts. I believe that is right in the ball park. All connections are clean and uncorroded. Any ideas? Next problem! On this same trip I found that my interior lights will not turn off! Not with the headlight switch or the little dash switch. The door switch turns off the buzzer but will not turn off the lights. I had to take the bulbs out. The key switch light stays on all the time. Any ideas on this problem? Could I have a electrical malfunction that could be causing both problems? This is a 91.5 that I bought new and still looks new has had no abuse and excellent maintenance. I have a grand total of around 45,000 miles on it. This is my first problem. I really would appreciate any thoughts on these two problems. It is strange they both happened at the same time. Thanks