Random Rough Idle (No Codes)

[Liv'n Life]

Looking for suggestions.
Symptom - idle will randomly drop (stumble) and run rough. Put in neutral rev a little and sometimes better sometimes not. Completely random. Will run fine, etc... then (usually in traffic) will start to stumble. Only died once. Started right back. Have let run in driveway in gear for 45 minutes and never did it. Drove the next day and did it in traffic.

Have done the following:
-Removed and cleaned TB including IAC.
-Replaced IAC (twice)
-Replaced TPS
-Replaced all 4 O2 sensors
-Replaced plugs (twice)
-Replaced Coil Pack
-Replaced connector to IAC
-Replaced fuel pump
-Checked for vacuum leaks (although that usually raised the idle)

Planning to do injectors next but not sure what else it could be.
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[macleanflood]

You check the vaccum box under the battery inside the fender?

What brand O2 sensors? You monitor live data before replacing them with an ODB scanner?

-Mac

 

[Vtx531]

Old gas?

 

[Liv'n Life]

You check the vaccum box under the battery inside the fender?

What brand O2 sensors? You monitor live data before replacing them with an ODB scanner?

-Mac

No vacuum box. Not sure if '04 has it. The line that runs over to the area it would be is capped. I know my '01 had that.

O2's were NTK both times. Replaced those because did have that code (and bad pre-cats - also replaced)

 

[Liv'n Life]

Old gas?

Jeep is driven daily and drinks a lot so I don't think it's a gas issue.

 

[Jerry Bransford]

Exactly what brand and model # spark plugs did you install? Newer 4.0 engines like yours are extremely sensitive to the type of spark plugs, single tipped platinum plugs like the Autolite AP-985 and Champion 3034, often listed as correct in some spark plug guides, will cause an intermittent bad idle and/or misfires.

 

[MountaineerTom]

No vacuum box. Not sure if '04 has it. The line that runs over to the area it would be is capped. I know my '01 had that.

O2's were NTK both times. Replaced those because did have that code (and bad pre-cats - also replaced)

I would think it would have one (or supposed to). My ‘06 does.