It's a 3VZE, 3.0 V6 motor that was recently built, less than 1 mile on the motor. When at idle, it is slightly rough idle. If I unplug plug wire 3 OR 4 the idle doesn't change, as if it is not firing (at idle) BUT on the head and piston itself, you can see that the cylinder is firing. When I give it gas, the motor smooths right out, runs like a dream. While under load if I unplug 3 OR 4 the motor will stutter, which it should. I cannot figure it out. I pulled all the injectors, tested the ohms and even ran the injectors out of the truck. I also have a fuel injector noid kit. You plug the noid in the harness and start the engine, if it blinks it is good. All injetor clips are good. Ignitor, cap, rotor, plugs and plug wires are all new and to specs. Anyone have any input at all?

 

Are you sure you don't have #3 & #4 wires swapped at the distributor? That's what it sounds like....

 

Have you checked your timing with the jumper installed? I had something very similar when I rebuilt mine, and it was due to the distributor being 1 tooth off. I was not getting any flash from the timing light. Once I moved the distributor that one tooth, timing light was working, and the idle smoothed out. Adjusted the timing, and all was well.

 

The wires are cylinder specific and can only be used for the proper cylinder, so I know they aren't backwards.

Checked the timing, it is spot on and my light is working with it.

 

Check the distributor cap for cracks, etc.

 

Cap is new, no defects anywhere

 

The only thing I can think of that's left is you have valves sticking partially open or some other form of leak on cylinders 3 & 4. Do a compression check to rule that out.

 

Compression is 150 on all cylinders and I just did both heads. It runs good it's just the idle. I've run out of things to check

 

Have you checked for vacuum leaks using carb cleaner to spray all the vacuum hoses, and listening for rpms change? Are you sure you put all the vacuum hoses back on the correct places?

 

Went through all the vaccum lines, replaced a few and have gone through tons of pictures to figure out how to hook them up and I'm pretty sure they are right.

 

Here is a diagram that I put together with help from other posts on this awesome website, just in case:

 

Do you think you can take a picture of your VSV too? I want to be 100% sure that the vaccum lines coming from there are in the right spot too. Thanks