well i back in the world this is my 3rd cherokee im in smyrna tennessee and my jeep i just bought is a 99 sport np242 aw4 4 inch lift on rubicon wheels with 32s but it gets crappy gas milage im thinking it could be this hair line crack in the manifold near the bottom thanks

 

Welcome back.
A crack in the exhaust can mess up the performance and mileage a little.
A small crack in the intake may cause it to run lean, with the computer trying to compensate by making it over rich. This may be the cause of your problem. JMO

 

its right were the two tubes go into one before the collector. i put gas in it and it was right under the full line and i drove on the interstate about 90 miles and it was down to half does that sound right thanks

 

That leak is causing havoc with your O2 sensor. It's not seeing the complete flow from your engine, so the computer can't really adjust the mixture correctly. IMO
Your Jeep is no economy vehicle, but it should do better than that. My V8 WJ goes 90 miles and the gauge is still near full.

 

can the little hairline be welded up and i never thought something so small could do that

 

Depends on the condition and thickness of the pipe. I'd say it's possible. It's just welding a used header. People weld cracked ones all the time when they can't afford to replace them.

 

well thanks for the info man

 

Welcome to the site

 

Welcome from Wisconsin.

 

Hi and welcome back, and I thought all jeeps were not thirsty