1998 cherokee 160,000kms 4.0 auto. running extremely rich, smells like it has a fuel leak when its running and has a bad rotten egg smell when you put the hammer down to pass or anything. new downstream o2. new plugs wires, cap, rotor, air filter. its eating fuel like crazy but seems to have the same power it had before, any ideas as to whats making it run so rich would be appreciated. and rotten egg smell doesnt always mean a bad cat.

 

How about the upstream O2? Might also be a stuck (open) injector.

 

yeah but wouldnt it have a misfire if the injector was stuck open? and would the injectors for a 94 fit a 98

 

new problem...... now loss of power and when it sits for a long time it will crank and crank n crank before it wants to start then i stop cranking n try again n it fires right up

 

Fuel pressure regulator was my first guess and a bad anti-drainback valve sounds like the second issue. Probably time for a new fuel pump.

 

yeah just started it up, ran like **** for 30 seconds died then turned the key and started right up
if you turn to on then off then go ahead and start its fine

 

ive had enough of this rusty old peice of crap, for sale sign put into er now 2000 into it in the last 2 months. time to move on

 

any cel's

 

That all sounds like you have an injector that is stuck open or "leaking down" The long crank after sitting is always a sign of that and running rough at first untill the fuel in that cylinder is burned off.

 

il do a injector leak down test tomorrow then