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Rough idle after swap

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So I'm going to tell a little story about my commanche. I'm going to try to remember to cover all the bases of every thing I've done recently and maybe you guys can help me figure out what's wrong. 


2 weeks ago my renix 4.0 spun a bearing and within 4.0 miles blew the motor dropped cyl 1. So commence the renix tear down and removal. I had acquired a 99 xj 4.0ho. I had researched that I could out a ho block and head combined with the renix intake for a simple quick swap. While doing this I threw a ton of parts at it. Parts being "hey this would be way easier to change out of the truck".

The list

Oil pump

Rear main seal


Timing chain


Valve cover gasket

Manifold gasket/bolts

T-stat /gasket(used ho housing wired temp sensor from side of block, using the ho sensor) 

Motor mounts

Water pump /gasket

Head gasket/bolts

O2 sensors.

Ground refresh as well


Got everything in the truck......it runs rough at idle and runs super rich on intial start up but after it warms up it stops running rich but continues to run ruff. But at higher rpm the rough Ness goes away. Any ideas as to what could cause this. Thank you for your time.


1989 commanche renix 4wd long bed ho block and head renix intake








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1 hour ago, cruiser54 said:

Tips 1 through 5. Did you get the ground wires on at the dipstick tube stud? clean and shiny?


which intake manifold gasket did you use? Renix or HO?


How's that line from the MAP to throttle body? 

Yes but I'm going threw today after work and adding more and replacing eyelets for grounds after reading threw some of your tips again.


Renix intake/exhaust gasket


The vacuum line? I just replaced it.

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6 hours ago, cruiser54 said:

check that vacuum line closely, especially where it connects to the throttle body. I have a tip for fixing that also.


Tip 5 should be done for sure. 


All grounds refreshed and 2 added.....no change.....I saw in one of your tips about the coolant temp sensor on the block......does it absolutely need to be down there? I wired mine to the thermostat housing. Does it need to move?

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I think ECT in Engine Block would have a more stable (no sudden/fluctuating changes in temperature) reading, then its current location in the T-stat housing (hottest spot of the cooling system). Engineering put it in the block. My 2¢.

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Okay, so after a few days of madness trying to find a 5/16 square socket I resorted to grinding an extension down. The CTS is in its correct home on the side of the block. That helped the start up but it's still not running 100% correct. Anymore ideas?

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