1996 olds 88 won't start

could be also could be asd system check the power on the asd fuse with the engine being turned over

is there a check engine light, possible mass air flow sensor

Filter or pickup is probably clogged.

Battery connections good , battery ground cable connection on the frame an engine clean an tight ? No corrosion . I wouldn't look for any ground issues under your seat . No power , main cable problem , to starter etc...

This same thing happened to me in my 1996 buick century just a few days ago. I have the same problem with the door locks and the radio resetting to AM too. I also have the problem of the seats not moving. I think it might be the curcuit breaker or a fusible link. I am not a mechanic, but I do have the repair manual and the mechanics book with the wiring diagrams. If you want me to send the wiring diagram I could do that. I hope that helps. Let me know what you find cause I got the same problem.

Your first problem is to find out why the intermittent no-power problem. Honestly, that sounds like a loose conmnection somewhere. check all your grounds for clean and tight conditions Also, battery connections and alternator connections. Double check your power distribution center for any loose wires or poor connections. Once you solve that problem, then you can diagnose the other problems with poor idle and temp. gauge.

check your fuel pressure it should be 48-55 psi with key on engine off.If its not within these specs it will need a new fuel pump and filter.

i don't have a solution but my car did the same thing in october 2009 and i still have not had it repaired. I am told it is something electrical because its your fuel pump is not coming on and that is why the car is not starting but it doesnt make since why the windows and power seats dont work. I have also been told the only thing that connects the 3 of them is the body control module.

look under the carpet on drivers and passenger sides for the ground blocks.
turn edge of carpet next to door over close to front and there is a metal plate with a bunch og ground wires that need to be cleaned for a good connection.

All I can suggest is to carefully check out the condition of all +12V power supply leads and ground connections, from the battery to the general power distribution bus at the fusebox.
Pay particular attention to battery terminal posts and any in line maxi power fuses/fusible links and associated connectors, terminals and connections.
Check you havent lost a ground connection between the battery, engine/transmission assy and the general body.
Also worth checking the alternator is working correctly, able to carry the normal running loads reliably. Battery terminal voltage should be approx 14 to 14.5V with engine running when headlights on, A/C blower motor running.
I assume the battery charge condition is ok when these problems occur.
Check electrical and physical condition of the actual Ignition/Accessory switch and associated steering column loom connectors.
Good Luck!