1991 Toyota Corolla Fuel problem - Black smoke & stalli

1991 TOYOTA COROLLA
23,876 MILES • 4 CYL • 2WD • MANUAL
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TERESA KINTZ
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Car began by stalling when slowing down for stop signs or lights. Would start again, but acted like it was not getting enough fuel, so husband increased idle speed. Still had problem, so put on Code meter which read a "Code 31". Replaced MAPS sensor, cleaned air filter, cleaned and regapped plugs and turned idle back down. Black smoke out exhaust has worsened, fuel smell is strong and car ate 5 gallons of gas in 80 miles! Any ideas for my husband to check now? He is a carburetor man and these computer problems have him baffled.
Jul 1, 2008 at 9:59 AM
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KHLOW2008
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Hi Teresa Kintz,

Is the code still showing?
Is MAP replaced same rating? Part new or used?
Check MAP wire for open circuit and vacumn leakage.
Jul 1, 2008 at 12:49 PM
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MMPRINCE4000
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In addition to what KHLow2008 said,

Running a car rich for an extended period of time will kill the O2 sensor and overheat the convertor, causing the convertor material to melt and clog up the exhaust.

On a 91 the convertor is bolted to the downpipe, so you can unbolt it and look inside the convertor, it should look like a honeycomb, if it is melted it must be replaced, but you must fix the rich condition first.
Jul 2, 2008 at 5:22 AM
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