I am running out of things to replace. I have a 94 4.0 that wont start unless you spray starting fluid in the throttle body and hold it wide open. Then once it is running if you throttle up to around 2500 it starts to run real rough? any ideas? I have changed every sensor and most other parts already. also I get a 42 code ( auto shutdown relay) when i check trouble codes

 

have you changed the idle air control valve or map sensor? could be a vaccum leak causing it to run rough once started. i would look into that relay and replace that and see what happens.

 

How much fuel are you getting to the rail? Just trying to think of other things

 

I didn't replace the map or idle air sensors but I swapped them with my 94 YJ and it didn't make a difference. Also I checked the fuel pressure at the rail and the XJ is it 40 just like the book says, but the YJ is at 80. Thanks for the help by the way.

 

I'd check my plugs and wires to make sure they are in the correct firing order. I accidentally hooked two up in reverse on a Fiero (yes.... i actually had one....) I had. It did the same thing. A diagram should be easy to find.