1990 Cadillac Fleetwood Too much fuel consumption

1990 CADILLAC FLEETWOOD
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SANYCH
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Engine Performance problem
1990 Cadillac Fleetwood V8 Front Wheel Drive 120k miles

I bought the car a month ago and am not sure if its gas consumption is good even for a Cadillac. Now it's 20L/100 km (11-12 mpg) for the city (haven't had a chance to drive on a highway yet). Meanwhile the computer shows that the outside temperature sensor is dead (codes: F10 and F32). Can this sensor be the reason? I checked the manual, it says there's a separate temperature sensor, called Intake Air Temp sensor, proposed to control fuel waste. But who knows, may be that, outside temp one (where is it located BTW?) can also be taken into account by the computer.

What do you think, guys?

Many thanks.
Jun 23, 2009 at 11:38 PM
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RASMATAZ
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Do you have a check engine light and when was the last tune-up??

Could be running rich due to the following:


Possible causes include a bad O2 sensor, excessive fuel pressure (bad fuel pressure regulator or plugged return line), leaky fuel injectors, dirty air filter or restricted air inlet, or a defective coolant sensor that prevents the engine management system from going into closed loop mode.
Jun 24, 2009 at 3:25 AM
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SANYCH
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No "check engine" yet. I put in a new air filter three weeks ago. Don't know when it was tuned up. Definitely more than a year ago, because otherwise the previous owner would have mentioned it. Is there any way I can check the coolant or O2 sensor on my own?

Thank you, rasmataz.
Jun 24, 2009 at 8:46 PM
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RASMATAZ
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You can test the coolant temperature sensor resistances cold and hot and the O2 sensor switching voltages by using a DVOM-multimeter
Jun 24, 2009 at 9:33 PM
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