1991 Buick Rivera Electical Problems

GETTING CODE 26. THE CAR WILL NOT IDLE PROPERLY AND WILL DIE WHEN AT IDLE. VERY ERATIC IDLE, AND NOT DRIVABLE AT ALL.

JUST PUT NEW FUEL PUMP, FILTER, PLUGS, WIRES, OIL IN ABOUT 1 MONTH AGO. WAS RUNNING GREAT>THEN IT JUST STARTED ACTING UP

ANY INFO WOULD BE GREAT

I corrected my similar problem on a 95 rivera by changing the TPS -throttle postion sensor-cost $60 for the switch.
Might also be timing chain.....replaced mine at 106,000. Ran rough at all speeds.

check the connection plug in the mass air flow sensor, mine was doing the same thing, until we discovered it was loose, now it dies after 10-15 minutes idle,