Flood water poor mpg

1998 JEEP GRAND CHEROKEE
185,000 MILES • 4.0L • 6 CYL • 4WD • AUTOMATIC
Avatar
MELLUVSJ3FF123
  • MEMBER
  • 2 POSTS
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?
Mar 30, 2018 at 10:23 PM
Advertisement
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 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
Mar 31, 2018 at 11:59 AM
Avatar
MELLUVSJ3FF123
  • MEMBER
  • 2 POSTS
P0171 and p0306.
Mar 31, 2018 at 6:09 PM
Advertisement
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 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
Apr 1, 2018 at 3:53 AM