Runs rough for about ten to twenty seconds then shuts off

1998 LINCOLN TOWN CAR
200,000 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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DOMAS DK
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  • 1 POST
No matter hot or cold. Also, sometimes it just runs fine, under no special conditions, just when it's in the mood. After it started i opened up the OBD, showed a system too rich, oxygen sensor lean and cylinder 1 misfire. Changed both front oxygen sensors, ran good for a day, then same again. Probably didn't change a thing, it was just in the mood to run. Then plugged OBD again, no faults. Changed fuel filter, restored the pump, changed coils, plugs, did IAC, throttle, MAF, EGR. checked all wires i could find, hoses, vacuums, everything seems okay and nothing out of place, leaking or not installed properly. Still all the same.
Nov 7, 2019 at 12:27 PM
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JACOBANDNICKOLAS
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Hi:

I noted you have a scanner. If it is a live data scanner, I need you to check fuel trims for me and let me know what you find. There are both short term and long term trims. I specifically need the short term fuel trims when the problem happens.

If you could do that, it may me help you figure out the problem. In addition, check to see what the engine coolant temperature signals to the computer. When you check it on a cold engine, the temperature sensor should be indicating aprox the outside ambient temp.

Do this and let me know what you find.

Joe
Nov 8, 2019 at 4:35 PM