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Flood water poor mpg

Tiny
MELLUVSJ3FF123
  • MEMBER
  • 1998 JEEP GRAND CHEROKEE
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 185,000 MILES
Drove through flooded water to the floorboards. Changed spark plugs. Now getting eight to ten mpg and smells like sulfur. Black smoke when engine revved. Could o2 sensors be bad? They were submerged. Any other suggestions?
Friday, March 30th, 2018 AT 10:23 PM

3 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon.

You need to change the oil/filter if it was that flooded. Also, the connectors and modules may have been damaged from the water. Are there any codes that are set in the PCM?

Roy
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Saturday, March 31st, 2018 AT 11:59 AM
Tiny
MELLUVSJ3FF123
  • MEMBER
  • 2 POSTS
P0171 and p0306.
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Saturday, March 31st, 2018 AT 6:09 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay.

The 171 is a lean code. That could be a vacuum leak, low fuel pressure from a bad fuel pump.

The 406 is a misfire for number six cylinder. That could be a bad spark plug, wire, injector, low compression or internal mechanical issue.

Roy
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Sunday, April 1st, 2018 AT 3:53 AM

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