GMC Repair: 1994 Corsica 3100, poor fuel economy, degree thermostat


Question
QUESTION: I recently purchased a 94 Corsica 3100 from an elderly lady no longer able to drive.  I have noticed very poor fuel economy from this unit.  There are no MIL on display, performance does not seem to be affected, but my last tank of fuel lasted less than 250 kilometers.  To add, this car has only 94000 km on it, so it was driven very little since 1994.  Could you offer some suggestions that may help because I do not have access to a scan tool at this time.  Thank you for your time.

ANSWER: If you can go by auto zone, if there is one near, they will scan and give you the diagnosis. I would check the catalyst. check to see if you are getting adequate exhaust flow. use your hand and check for adequate heat as well. I had the exact same model when i discharge from the army. I particularly like the model, however, you must do take good care of them, and they will serve you well.

 You really need to scan. I can only give you a guess at this time. There are so many variables to possible solutions or starting points. I could do the shade tree up to the late 1980's.

Is there any performance or oddities in performance? Normal during start up?

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QUESTION: Warm up does seem to take a long time...I'm up in Alberta, Canada and I don't really hit operating temperature until I have driven for 5 minutes.  I'm sure the thermostat is working because I've seen the temperature go up, and then dramatically drop (opening of thermostat).

Answer
I am in Oklahoma, USA. Even here some of the diesel trucks and other light trucks and cars do this:

Cut a piece of cardboard or other material as to cover half of the radiator. The radiator is doing its job very well. I had a car just like that. You could also get a 180 degree thermostat.