1996 V6 rough idle

[banetranch]

banetranch is on a distinguished road

Slight idle problem in park 1996
Well this is what I have done, bought this 1996 4runner an the engine was sounding very smooth. But I had one problem, I was adding 16oz of coolant everyday.. I found a leak on the head caskets, replaced head caskets, intake caskets, belts, timing belt, water pump, knock sensors, fuel injectors, pvc valve, an hoses that looked bad.
Start right up an now there is a semi slight rough idle, took it to auto one with the CEL they gave me the codes that 2,4,6, cylinder miss firing. Well the engine does not sound like 3 of the cylinders are misfiring, maybe 1 of them, I still have some power.
I checked for vacuum leaks and replaced all caskets with no results.
Any one with some ideas?
Thanks

 

[nissanh]

If there is a vacuum the engine will rev at a higher RPM. So you don't have a problem with the vacuum.
Check the spark plug wiring and the gaps in the spark plugs. What is the make of the plugs?

 

[banetranch]

New plugs

I put in the NGK plugs prior to taking out the head caskets, I had approx 200 hundred miles on them with the engine running smooth. I have also replaced the coils during the teardown, wires looked like they have had been replaced recently.