Daniel Sims

I've tried to post this before but it kept deleting my entire post. I've typed this up so many times so I'm going to try to make this short.

2000 cherokee xj 4.0
Swapped 0331 head for 0630 head due to crack in 0331. Ran great before even with crack in head and never let it overheat. No codes. Pulled head and oil pan and inspected all bearing made sure there was no damage. Replaced rear main while I was down there cause of course it was leaking ha. Put it all back together and it ran like garbage. Rough idle and sounds like it's misfiring. It sputters when accelerating and the is a serious lack of power and jolting and bucking when accelerating. Never got it over 20mph because I thought the jeep was going to fall apart. I have no CEL.
So I went through the process.
-Fuel and fuel pressure (42 at prime and 49-52 at idle) -check.
-compression on all cylinders- check
-new spark plugs gapped-all injectors are firing
-pulled throttle body and cleaned all sensors
-new TPS, Cam sensor, Crank sensor, coil pack, 2 new o2 sensors, new gaskets (head, valve, oil pan, intake/exhaust)
- checked all vac lines
- ran sea foam into intake from brake booster line to see check for intake leaks and exhaust was cracked. Pulled it back off and welded it up. Reinstalled and still ran the same.
- reset pcm and still no change.

Don't know what to check at this point. Still no codes
Any ideas or think of anything I missed?
Typed this on mobile so sorry if formatting is off.

Cummins93

When you first start the engine does it run rough or does it run well for a short while.

Daniel Sims

It runs rough as soon as it starts. When I bring the rpms up it will have very quick dips that sounds like a misfire.

4.3L XJ

How is your fuel pressure?

Ralph77

I am wondering what exhaust you used with the 0630 head.
The exhaust ports are bigger on the 0630 head. The '00 exhaust does not cover them.
Also don't guys have this problem when they don't put the intake back on properly?

lawsoncl

Plug wires in the correct place? Note that Chiltons and Hayes have the wrong firing order.

Daniel Sims

Fuel pressure is good checked it multiple times.

Daniel Sims

I used an exhaust that came off a 96 with a 0630 head. I scrapped the 00 exhaust for the 0331 because they are too small of exhaust ports for the 0630 head.
I don't know how I could have installed the intake wrong. It goes on one way and I've probably done this 5 or so times and have never had a problem.

Daniel Sims

It's a coil pack so it only goes on one way. I haven't messed with the index of the cam position sensor (sets the injector firing order) and it ran fine before. The last thing I'm thinking to check is maybe I overlooked something when reinstalling the rocker arms...

4.3L XJ

What brand sensors did you use?

Ralph77

As far as the intake manifold I have read that guys just don't get the back of it seated properly and seem to have issues similar to this.
Guessing all the O2 sensors are still hooked up?

Dave51

I'm going with crank and cam sensors not synced.

Cummins93

While the engine is running pull the injector plugs 1 by 1. Observe running condition changes. Which plug removal doesnt make a difference?

Let the engine cool.

Take the valve cover off and bring the engine to TDC cyl1 manually. Removing the spark plugs will make this much easier. Bring the engine through its firing order and watch for intake and exhaust valve actuation.