2007 Jeep Grand Cherokee Significant Mpg Decline Occurred Last Month Done Tunes

2007 JEEP GRAND CHEROKEE
100,000 MILES
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DIANE J
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  • 3 POSTS
Significant mpg decline has occurred in the last month, I have done a tunes up, check brakes, air pressure. Is there any thing else that would cause a decline mpg? It appears to continue to decline.
Nov 26, 2012 at 7:33 PM
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RACEFAN966
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Is the engine light on? You say you did a tune up what did you replace? I wouldn't hurt to get a can of seafoam and put it in the gas tank next time you fuel up.
Nov 26, 2012 at 7:36 PM
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DIANE J
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Engine light is not on. I have tried seafoam. Tune up included spark plug changed and belts.
Nov 27, 2012 at 3:01 AM
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RACEFAN966
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When you replaced the plugs what did they look like ie- black, white or? Have you replaced any other parts? which engine is in it? How is the power?
Nov 27, 2012 at 7:52 AM
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DIANE J
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Dont know the color but I have not replaced anything recently. Power is okay. The rpms are normal. V6 engine. I did have the trans module replace in January
Nov 27, 2012 at 7:34 PM
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RACEFAN966
  • ✓Experienced Mechanic
  • 5,029 POSTS
I do believe that this Jeep has a mass air flow unit. What I would like you to do is buy a can off mass air flow cleaner and then remove the mass air flow and spray out the inside of it (cleaning it) and put it back and let me know how that does. If the sensor wire inside it dirty or? then that can reduce the mpg and sometimes alot.
Nov 29, 2012 at 7:37 AM
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