Topic: Wierd Idle and Lowered MPG, cant figure it out.

[jeepboy21]

So about a month ago my gas mileage suddenly dropped off from about 17mpg to barely making 14mpg.(with corrected speedo)  The jeep used to idle @ about 800 now it idles anywhere from 1500-2000.  I did not do any wheeling or mods that caused this it just started happening.  I have cleaned the TB, replaced TPS, O2 Sensor, "rebooted" the computer and checked thats the sensors are all plugged in.  I have also done an oil change and new cap, rotor ,plugs since during the time this has been going on with no change.  I dont know what to do next.  Do i need to replace the IAS, MAP, AIP?  Could this be a sympton of a craked exhaust manifold?  please help.  thank you.

[Jeffy]

You clearly have a vacuum leak someplace.  Check all the lines.

[jeepboy21]

thanks

[jeepboy21]

after looking under the hood i am overwhelmed.  should i just grab the haynes and go to it or is there a better way?  are there vacum lines that "normally" need replacing on a YJ w/ 175K?

[Jeffy]

What year is the jeep?  One way to find a leak is to strap a soapy solution onto hoses.  Or you could use carb cleaner.

[jeepboy21]

sorry i forgot to give the specifics.  its a '93 YJ 2.5L, 5 spd, 4.10.