You have a problem with a 92 Lebaron Convert V6 and at first you had to start it in Neutral now it won't start or stay in any gear is this the shift linkage?

The most likely cause is a misajusted or faulty neutral safety switch, or your linkage is coming loose and preventing proper indexing. Your description is how most mechanics troubleshoot a "will not crank situation". If it will not crank in Park, move the trans lever to Neutral to see if it will crank. If it does it's the switch. Your car just did the test for you and now the switch has either moved just enough to prevent starting or by your description of not staying in any gear the shifter assembly needs to be repaired. Since you have two problems combined, one starting and one being a gear selection problem, I would lean towards the shifter assembly in the console is probably loosening up. If you are mechanically inclined you can figure out the screws that need to be removed to access the shifter assembly and remove the console to inspect it. Because it has loosened up, it has affected the neutral safety switch preventing your car from cranking. I did vehicle maintenance for 27 years and I will pretty much bet that this is your problem. The neutral safety switch is screwed into the trans. Front side, just above the pan. There are two swtches that look the same, however the Nuetral safety is the one closest to the tire or outside of the car. Trans model A604 Dan the tranny man