I'm new to this site, looking for help. Ihave a 1994 xj 2wd 4.0. When merging onto the highway at speed 45 to 65 mph all seems to load up backfire through intake and exaust pipe loose all power no matter how much throtle is given . New exaust manifold tps, cps emc, plugs, cap , button, will not run right again unless I shut off and restart then fine till next time

 

Does it do it everytime you accelerate?it could be a fuel problem.

 

Maybe a plugged catalytic converter? I would think it would do this more often though if that was the case...

 

Have you rechecked the torque on the manifold attaching bolts/nuts? Might not be the cause, but it's a possible source of a vacuum leak causing lots of issues. JMO

 

Thanks for suggestions, there is on cat , checked for vac leaks none, dose not do it every time driven. It will also go into this miss fire no power if I rev the ergine to hi prms in neutral and let return to idle. I have to re start to get it to run right again.