My 2007 jk started using twice the fuel. I ran a check and Evap monitor fails 87 &90 & 86 & 85 Also EGR Fails 95 & 96

And on overall check
Evap = X
CAT = X
HTR = x
O2S = X

Also my gascap code has been on dash for ever I replaced gas cap and EVAP CANISTER. What could it be and are all problems related? Finally could my Catalytic converter be going out and clogging exhauset?

 

My best SWAG is your cat is clogged

 

What codes are stored and what are the codes you've listed above? A clogged cat should show itself in the form of a red hot ball after driving. What's the exhaust smell like, rich?? Any codes for O2 sensors?? Are they connected? Evap code could be any thing in the system, so hold off on going down that road.

 

+1 on this, also it could also be something not code related, like the brakes dragging. Do you have a scanner or logger that is able to view the O2 sensor data? The trim data could help ID something like a leaking injector. Id also pull the plugs and inspect them.

 

As mentioned above what are the codes? Most of these seem emissions related and I haven't see a major impact to gas mileage due to emissions issues. I had an O2 sensor go bad and it lowered my gas mileage but not in half. Are there any odd smells from the exhaust, what about gas or even brakes heating up? What about overall performance, is it the same?