So my gas mileage dropped from around an average of 13.5-14.5 to 5.6 at my last fill up. 02 sensors have been recently changed.

I'm pretty sure my catalytic convertor is on it's way out, but I didn't think it could cause that hard of a drop.

Something that is also relevant to both the hard idle and mpg would probably be that it kinda sank in water up past my seats, and I know that probably had something to do with it, but I don't know what went bad.

It's a 97 with a 4.0 and AW4 trans. Thanks.

 

Have you done a complete tuneup since?

 

Not yet. I know definitely need to change all the fluids, but I did think the plugs and wires and all that would need to be changed also. Filter has already been cleaned

I also forgot to add that under heavy acceleration I got a slight grayish cloud of smoke out the exhaust.

 

When looking at your exhaust, black smoke usually means its running rich, (bad plugs, plug wires, bad o2 sensor etc) white gray usually means head gasket - i.e. coolant in the combustion chamber, blue gray usually means oil in the combustion chamber - usually its a plugged PCV valve, bad rings etc. -

 

You really shouldn't be driving it after a flood that deep without changing fluids. Water WILL destroy your transfer case, transmission, differentials, and engine. Get that done and do a FULL tuneup with copper plugs, wires, brass distributor cap, rotor, and check all electrical connections for corrosion. A ground refreshing never hurts.