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Loosing mpg

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Old 03-13-2016, 09:22 AM
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Default Loosing mpg

I have a 98 Cherokee with a 4.0 and it is loosing mpg it use to do good. But I'm using double the gas now than what it took 3 months ago. I have a miss at idle sometimes not always. But when it does the check light comes on but the next time I start it it goes out. Need help on what could cause this. Thanks
Old 03-13-2016, 09:37 AM
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
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Pull some codes. See your local Autozone or Advance Auto. They will pull the codes for you. Report back.

Some typical suspects for severe loss of mileage:

  1. Vacuum leak.
  2. Bad 02 sensor.
  3. Bad 02 heater.

Codes will tell you a lot.


Check your tailpipe, too. Lots of black soot? Do you leave a black cloud behind you when you accelerate hard?



By the way, it's "losing", not "loosing".
Old 03-13-2016, 09:52 AM
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Thanks I'll check the vacuum lines,and the o2. Oh and thanks for pointing out I missed spelled a word. That's why I posted to have my spelling checked. Lol
Old 03-13-2016, 11:46 AM
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You post to learn, don't you?

Get the codes, or you'll be shooting in the dark.
Old 03-14-2016, 07:52 PM
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I'll try to get the codes when the light comes on again. Thanks
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