2000 Bravada shuts off while i'm driving and won't restart. While trying to restart, the instrumentation lights are completely out. Once they return, it will start. What's going on? Also, the gets stuck in the ignition every so often too.

Could be a few things. The mass airflow sensor could be dirty or faulty. Once you shut off and start again it returns to factory specs and will run for a little while before same thing happens. Could be a bad fuel pump. When they are going bad they overheat and shut down. Once they are cool, the pump works for a while till the same scenario occurs. Do you have a check engine light? If so, what are the codes?

Had a similiar problem with mine. Ignition control module will overheat and the vehicle will not be able to restart until the vehicle and ignition module cool back down. Ignition control module probably bad.

it can only be a handfull of things, a faulty relay, ignition switch, solenoid, or bad connection

Is then engine light ON? if so check for codes and if not then it has to do with fuel/air delivery.

these have a safety system so the shifter won`t go into any gear unless the brake is pushed(indicating someone sitting in the drivers seat),if the brake lights aren`t working this indicates that the fuse that operates the shift lock solenoid and brake lights is not working and needs replacing.check the fuses and replace the fuse and things will probably return to normal.

This is an electric shift transmission (4L60E). If the harness is not plugged in well enough or has dirt in the plug it can lose contact causing it to seem as if it is bogging. What is essentially happening is that it is starting out in 1st initially, but when you slow or stop it doesn't go into 1st again and tries to go in 2nd. You can go undewr the truck and check th connection. If this doesn't resolve the issue, I would return the truck to the repair shop and have them check to assure that the plugs are correct in the valve body driving the shift solenoids.

My 2002 Millenia just started doing this the other day, while on the freeway when it started doing it i would shut engine off and restart it and it would be good for a while then it would do it again, i am still looking for solution, has any one found one?

your problem is more than likely one of a few problems
there are two hoses on your transfer case one sucks in one blows out if one gets cloged it will go out completly so have it checked its starting.
or check the oil in the transfer case

i got a 98 bravada and my AWD light was on, what i did to fix it was replace the transfer case motor and thats all, i did a bunch of research and found out that the transfer case motor is the main conponent with of your AWD it tells the transfer case when to give the front wheels power. try replacing that

Try a vehicle speed sensor (mounted on the transmission), this sensor (or in 1% of cases its wiring) might be bad. This would cause your problem.

If this does not fix the problem, you probably effectively need a new transmission or a transmission rebuild.