On occasion, my 1998 bonneville will turn over well but not fire. Sometimes ,it will start and run a few seconds, then die or start down the road a short way, then die. When this happens, I've noted that the interior lights may come on when the ignition switch is turned to the on position and quickly fade out through the timer instead of staying on as they should. Also the power windows and locks are inoperable, but the most interesting part is that the power seat is also dead. I might think that the problem could be related somehow to the ignition switch, but the seat should be hot all the time. Whenthis happens the switch can be cycled from off to start many times with no effect.I've tested conditions by keeping one of the window switches engaged while slowly turning the ignition switch back and forth and sometimewhen the window motor starts to engage, yoou can stop and turn the switch to start and it will run without problem for months. I suspect perhaps an inconsistent ground or partially broken hot lead, butit is so inconsistet that I am a little lost. Any suggestions?

check and make sure your battery terminal connections are tight and clean...make sure that the bolts have not stripped out as well