So, I need some help.. actually, a lot of help.
I'm having low idle issues. Staying around 714 to 750.
Back story. Bought the jeep knowing motor was bad. Went to salvage yard and pulled a motor out of another 97.
Got it home and pulled the head off and inspected cylinder walls. Replaced head gasket and head bolts, torqued to spec. Replaced distributor while I was at it. Cleaned throttle body and replaced idle air control, throttle postion sensor and mass air flow sensor. Replaced both 02 sensors, new plugs and new wires. All cyclinders are firing. Checked and cleaned all ground connections, and also the 2 in the trunk. Replaced PCV and tube.
Checked for any vacuum leaks and found none.
When I pull #1 or #3 injector plug, idle does not change. I replaced both of those injectors with the injectors from old motor. No change. Pulled 2,4,5, and 6 and had a drastic change.
Could it have a weak fuel pump or should I change all the injectors. Im running out of options. I have not checked fuel pressure or compression as of yet.

 

If it's really only #1 and 3 that aren't firing.....

1) it's not the fuel pump but check the pressure with a gauge so you can cross it off the list

2) I'm assuming the new distributor included a new cap and rotor? If not replace them.
3) make sure plug wires are on correctly (firing order)
4)I don't know how you "checked the valves" but do a compression test.
5) and last, but probably first, are those 2 injectors "firing" use a noid light or just listen ( screwdriver in ear test)

You need to do some diagnostics before you throw anymore parts at the thing.and look very carefully at the wiring going to those 2; injectors.

​​​​​ Are you getting any codes? If you have 2 dead cylinders you should at least get misfire code.
​​​​​

 

yes, new distributor everything.
I have not double checked my firing order. I'll do that 1st thing today.
When I said firing, i meant I have spark out of all six of my plug wires.
I pulled the vacuum tube from my pvc to my manifold, which caused the engine to rev higher. That's when I noticed a very slight change when removing #1 and then #3 fuel injector plugs.
I am currently not getting any codes.
My plan for today is to also check compression.

 

...you may have done so already but since I assume you had the manifolds off when you had the head off check very carefully for leaks between the manifolds and the head... intake and exhaust.
....use your scan tool to look at the fuel trims
From your posts I'm having a hard time telling if 1&3 are dead, or just sorta dead sometimes.

 

With normal idle (Everything connected) i can pull #1 or #3 and it doesn't change anything. If I pull the pvc vacuum from the manifold, which causes the jeep to idle a lot higher, i can then pull either #1 or #3 and notice a slight change in idle.

 

Based on all this remote diagnostics..

The fact that you've tried swapping injectors around with no change and that at high idle disconnecting 1or 3 does make a difference suggests those injectors are working, although I would still listen to them at low idle.

Assuming they are working that suggests to me either a vacuum leak that affects those 2 cylinders (manifold) or leaking valve... either burnt or crud on valve seat. A compression test ( engine hot, throttle wide open) may or may not show something.

There was a TSB way back when that addressed funky idle/ crud under the valves

I'm about out of remote diagnostics ideas.

 

So today, i pulled off the fuel rail and cleaned every injector and then tested them all. 4 of the 6 were reading between 12-13 ohms. I replaced the 2 that were reading low.
I then did a fuel pressure test. Guage was showing right around 50 psi. But as soon as I turn it off, the fuel pressure dropped to 5 instantly, which tells me there is an issue with the fuel pump bleeding off.
would this cause a rough idle?
I also pulled cap back off rotor and wiped down everything. I triple checked the firing order and that's correct.
I checked the torque on manifold and that was good as well.
I'm starting to think it's a valve issue. I don't know what else to check.

 

If the fuel pressure drops like that I'd think the thing would be a bit slow starting.

But in any case:

Pressure drops like that could be fuel pump check valve or an injector leaking down. Seems unlikely that pump problem would only affect 2 specific cylinders.

Just for yucks, if you haven't done so already check for vacuum leak on intake to head joint by spraying brake cleaner or something on joint and listen for RPM change. Try to avoid blowing yourself up. Always possible leaks even though torque is ok.

And, as planned, carefully check compression.. a jungle leak down check, compressed air fitting in plug hole, valves closed, piston at tdc, listen for air at throttle body, would be even better

 

I did find this random plug not hooked to anything? Not sure what is for.

 

Flux Capacitor
(Might be connector for under hood light, I'm too lazy right now to get snow off mine to look)

 

just wanted to follow up and let you know I found the issue. I pulled the head off and discovered i had leaking valves on cylinders 1 and 3. I had and extra head and put it in. Solved the issues. Thanks so much