Dan89XJ

Trying to figure out why my jeep is running so rich i only get 200 kms to a tank it sounds like i have a exhaust leak under the hood i havent really checked into it much, but i have heard the manifolds are bad for cracking would this cause it, i have replaced the o2 sensor it helped some but it is still running pretty rich. any help is appreciated....

JeepCoMJ

yes and it will (read: already has) foul out your 02 sensor.

you could try and have the manifold welded @ the crack, but I can 100% guarantee that it will eventually crack again, right next to that repair.

replace both the manifold and 02 sensor.

BuckB91XJ

X 2, The crack in the exhaust manifold is making the O2 sensor pick more O2 so it is telling the ECU that the mixture is too lean, resulting in your too rich condition. Fix the exhaust leak and that should fix your problem. If not, put in a new O2 sensor.

truckntractorhick

yea i'd just replace it all then. cause like said its pulling in outside air!

98 JeepJeep

reccomend to replace BOTH motor mounts when you have it torn down...90% of cracked headers are from bad mounts....im talking from experiance...