Why would a 94 Lincoln Town Car stall after it warms up for 3 or 4 minutes while at idle?

Answer 1

SOUNDS LIKE A LEAN CONDITION CAUSED BY 1 OR MORE FACTORS: (I ASSUME THE FOLLOWING ITEMS ARE UP IN GOOD WORKING ORDER: ENGINE COOLANT IS FRESH AND FULL, THERMOSTAT OPENS AT THE CORRECT FACTORY REQUIRED TEMP, NO MANIFOLD OR HEAD GASKET LEAKS, ENGINE IS NOT BLOWING OIL THROUGH THE VALVE GUIDES, YOUR OVERHEAD VALVE TIMING CHAIN IS NOT STRETCHED OUT OF SPECK, THERE IS NO CORROSION AT ANY OF THE TERMINALS AND SPARK PORTS ON THE DUAL IGNITION COILS, PLUGS AWSF-32C WERE VERY RECENTLY CHANGED AND SET AT .054 GAP, YOUR AIR FILTER IS SQUEAKY CLEAN AND THERE ARE NO LEAKY VACUUM LINES) 1) EGR DUMPING IN TOO MUCH AFTER ENTERING CLOSED LOOP CONTROL. YOU HAVE TO CLEAN WHOLE EGR SYSTEM, CHECK EGR TUBE FOR VAC LEAKS/BREAKS/RUSTOUT, CLEAN THE EGR DUMP VALVE FILTER, CHECK AND/OR REPLACE EGR VALVE. 2) OXYGEN SENSORS BAD. MUST REPLACE BOTH AT SAME TIME. 3) DIRTY MAF SENSOR. BE CAREFUL WHEN CLEANING THE SMALL WIRES. DO NOT TOUCH THEM. ONLY SPRAY WITH DENATURED ALCOHOL OR AN AFTERMARKET ELECTRONIC CLEANER. NO CARB OR THROTTLE BORE CLEANERS AS THEY WILL CHEMICALLY DAMAGE THE COATING ON THE WIRES AND EARN YOU A $200 TRIP TO DEALER/PARTS STORE FOR A NEW SENSOR. 4) THROTTLE AIR BLEED VALVE/SOLENOID IS STICKING OPEN. IT'S ON THE REAR OF THE INTAKE MANIFOLD. CLEAN WITH WD-40 OR REPLACE WITH NEW UNIT. IF IT IS AN ORIGINAL UNIT TO YOUR CAR, DON'T WASTE TIME CLEANING. JUST GET A NEW ONE AS IT'S WORN OUT. 5) REPLACE PLUG WIRES WITH NEW MOTORCRAFT WIRES. I'M BETTING YOU HAVE 10 YEAR OLD WIRES TOO. HOWEVER: 6) SINCE YOUR QUESTION IS UNCLEAR, IF THE CAR STALLS UPON TIP OFF IDLE ACCELERATION, THEN ALSO CHECK AND REPLACE THE THROTTLE POSITION SENSOR. BE SURE TO GET IT PROPERLY ADJUSTED OR YOU WILL SUFFER A RACING IDLE SPEED OR A TOO LOW IDLE SPEED. IF CAR STALLS WHEN IDLING, NEED TO KNOW IF IN OR OUT OF GEAR. IF IN GEAR ONLY, IT MAY BE AN INDICATION OF TRANSMISSION TROUBLES. 7) AFTER ALL SAID IS DONE, CHECK IDLE SPEED EXACTLY AS SPECIFIED IN THE FACTORY MANUAL. IF ALL HAS BEEN DONE RIGHT, YOU WILL DISCOVER THAT YOU WILL PROBABLY NOT HAVE TO TOUCH THE IDLE SPEED SET SCREW. GOOD LUCK. BY THE WAY, I ALSO ASSUME THAT YOU HAVE A GOOD PCV VALVE AND THAT ALL PCV VACUUM LINES ARE CLEAN AND DO NOT LEAK. WATCH FOR THE ONE ON THE REAR OF THE INTAKE MANIFOLD. IT IS PARTIALLY HIDDEN. THE USUAL CULPRIT THERE IS A 3/8TH ALL RUBBER (SUPERB ENGINEERING TO SAVE A FEW PENNIES OVER A STEEL, BRASS OR COPPER) T-FITTING WHICH BEGINS TO DISINTEGRATE AND LEAK OVER TIME. IT HAS TO BE REPLACED. I USUALLY MAKE A NEW ONE OUT OF BRASS OR NYLON WITH BARBED ENDS. SOME PARTS STORES HAVE READY MADE NYLON T'S WHICH YOU CAN USE WITH NEW VAC HOSE.