92 grand caravan 11 mpg help?

I have a 1992 Dodge grand caravan with a 3.3 engine and auto transmission. The overhead display shows I am running from 10.1 to 12.3 mpg. Checking with a full
load of fuel and then refilling, I find the computer is correct. I changed the plugs and injectors. After googling around I find it may be the oxygen sensor. I am now trying to find if this likely the problem and if so, where will I find the sensor and are there more than one? What do they cost? I something like $125.00 Canadian. Any help or hints will be greatly appreciated.
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Check out http://www.allpar.com/fix/80s-codes.html
it will show you how to check for diagnostic codes.
Gordo

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It looks like a spark plug in the exhaust manifold, between the engine and the firewall. If you were in there changing plugs, you were almost on top of the sensor.
G

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Gordo wrote:

I see 1 2 and that is true. The battery was just replaced so that code said the battery was just recently disconnected. And 4 1 is next. Alternator field bad. Maybe the reason for changing the battery? Now to 2 5..automatic idle could be vacuum leak. The van has really bad idle so this could be but it does not mention 5 2 or anything about the o2 sensor.

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Google Groups your codes. Lots of stuff out there and advice on how to troubleshoot the problems.. I just found out I had a Fan circuit problem checking out the codes myself. Well no O2 for you!
Good luck.

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Fault Code 25 Synopsis Description: AIS (Automatic Idle Speed) motor circuit shorted or target idle speed not reached Power loss light: Off Limp-in mode: None
Possible Causes Vaccum leak - Check all vaccum lines for cracks or breaks. Bad connection or wiring - Check the wiring and connections between the logic module and the motor. Clean and regrease any corroded connectors with dielectric grease and repair any shorts.
Shorted or frozen AIS motor - The AIS motor is located near the TPS. For 1987 or earlier Turbo I engines, remove the bolt and slide the motor out (you may have to wiggle and twist it). Remove the clamp and carefully pull out the motor. Be sure and observe how it goes together, especially the orienation of the rotatiing valve inside. Hook the motor to a 12V supply to see if it runs. If it doesn't, replace the AIS. Clean all the gears and shafts throughly and reassemble the gear and valve assembly. Spray all the gears and parts with TriFlo or a similar silicone spray lubricant (don't use WD40 because it evaporates) and insert the motor. If the engine seems to race wildly after assembly (give it some time to get control), you probably installed the internal, rotating valve backwards.
Diagnostic Method Trigger Parameters - Near 0V or near 12V not detected when the motor driver is turned on or off, respectively OR
- Target idle speed not reached after a number of attempts
Results If Component Fails Fault code 33 is stored. Comments The logic module cannot detect an open circuit in the wiring, so a fault code may not be stored on vehicles (unknown which) with logic modules that don't keep track of how many times it has tried to adjust the idle.
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replaced anyway as it is 13 years old, and is worn out. Most replace every 60,000 miles.
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David wrote:

hope it fixes things.
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