The 55mph stall?

[pastordad]

I have an 89 Buick Park Ave. It will stall going down the road. Not much warning somtimes a sputter but more like the key was turned off. I can slide it into netrual and restart sometimes it is fine for miles and other times it repeats. The fuel filter is new. It is showing a check engine light and i was trying to find the plug to check the code. It is no where to be found. Any help would be awesome...Thanks

[wrightz28]

The connector is in the center of the dash underside (just below the ash tray.)