I'd do the following:
1. Pull the spark plug on #4 and inspect, should be wet and no carbon if its not getting ignited.
2. Pull the fuel pump fuse, and see if you can get the plug to fire against ground with the coil on the plug (not installed in head).
3. If it fires, you don't have a spark issue ( not saying the timing is correct or not)
4. If step #3 is success, then while the plug is out check the compression on that cylinder.
5. If compression is good, swap injectors between 4 and 6 - retest.
6. if you have fire, compression, and fuel... then either the fire timing isn't happening - or your thoughts on which one isn't working is wrong.

 

Answers:
1. Upon inspection white powder looking, so ignition is happening.
2. Did not perform test based off #1 results
3. N/A. Hd thoughts that it could be a timing issue but just got back from shop and tech had it on Actuel scanner and the only he noticed was both banks a rich..."possible vacuum issue"
4. Compression test was performed yesterday on #2 and #4 both have 125 PSI.
5. have swapped injector back to original injector that came out , same issue
6. So like I mentioned in question 3. Tech could not find any issue with misfire or timing issue. He thinks it is most definitely a vacuum issue causing this based on both banks being rich....I have tried to follow some of the vacuum images on the net but they don't seem to match my truck 100%. Does anyone have actual photos or the vacuum lines on their 2004 4.7L 2x4?

 

White deposits could be from a couple different things... Burning a bit of oil, running too hot/lean, or bad gas are some possibilities. Given it is only one cylinder..... I think you can exclude bad gas.....

 

You could go over everything with propane and see if you can find a leak.

 

So I had it running and sprayed brake cleaner over everything "as per the mechanic" and got no change in idle. So, brake boost hose is going to intake, there is another vacuum line going to the TB and then there is the PCV is connected to the back of the intake and the engine breather is connected to the cold air after the MAF.....send your questions if you have them.

 

Not sure brake cleaner is flammable.... Also, did you disable IAC for the test?

 

Did not!!!

 

So to confirm, you've pulled each coil off and the only cylinder that you can not tell anything happened is #4 ?
If that is the case, I think I'd pull all the plugs and expect to see something different about plug #4.

If its really just #4 being an anomaly, I'd be tempted to look closely at the intake manifold. Is it plastic? Maybe cracked or have a bad seal against the head at #4.

So are you getting any codes out of the computer? You can sometimes see codes without the engine light on. I always recommend an ELM bluetooth obd2 reader and torque. You can see the fuel trims, o2 sensors, etc... pretty valuable to start understanding what is going on.

 

Funny you mention fuel trims. Here is a sample reading while running from my ThinkDiag scan tool. I think you will be surprised at what it says. I was also thinking d Td he same thing about the intake. Can you help me understand what I am looking at?