Changed spark plugs and now getting misfires

Hi folks - I went and changed my plugs today. They had 138K on them and it was time. The procedure was uneventful and with the right sockets and extensions and torque wrenches gathered and borrowed before hand it was really quite easy. Only problem is the results. How can changing the plugs results in an increase in misfire counts. With the VCI cable and the software on my laptop, I am seeing misfires on mostly 3 of my cylinders and tonight I saw a couple on the cylinder that was seemingly working without errors. I did everything by the book. I removed the relay box and the loosened the 2 screws holding the wiring chase / channel near cylinder number 4 before starting. I did one cylinder at time. Removing the igniters, then the old plugs and installed the new plugs. I installed the denso's iridiums which I purchased from Toyota and opted not to change the gapping. I did check the factory gapping and they were all pretty much where they should be. I used a snap on inch lb torque wrench to torque the plugs at 13 ft lbs (156 in lbs) and the igniters at 82 in lbs. I set the relay box back to 74 inch lbs. I borrowed the inch lbs snap-on torque wrench and just to be sure it was accurate I torqued a body bolt to 13 ft/lbs with my craftsman 3/8 drive and then did it again with the 1/4 ft lbs snap-on to 156 in/lbs - the equivalent of 13 ft/lbs. Both wrenches clicked at the identical point on the test.

So what went wrong with my work that could now be causing more misfires ? I'm scratching my head so I'd really appreciate some guidance or speculation. Is there some other component(s) that may have also been needing replacement that are only now showing up bad because the new plugs are performing way better than the old ones (could I have 3 marginal igniters) - or did I mess something up- which is certainly in the realm of possibilities I suppose ?

Thank you in advance for your help. I just don't want to start guessing and replacing stuff. I was going to do my wife prius' plugs too but I'm holding off until I can figure this out.

 

This morning when I was doing my testing, it seemed like # 3 was working flawlessly and the 1,2,4 where not. But I did see #3 have a couple tonight. The software and locked up on that last run of the night but I did see it on the frozen laptop screen that 3 had a misfire. I was thinking of using the igniter from #3 to do some testing but now I need to make sure that cylinder is not having same issues as the other. I had a pretty long run this afternoon on the highway without any errors on any cylinders so not sure how any of this figures in - just putting it out there.

 

I did not use any dielectric grease on the connections. I didn't see any obvious burns or cracks on the igniters. The short length wire to #4 and the tight bend to get it to connect to the #4 igniter is the only thing that I can visually say is not ideal.

 

I was very careful to not to abrade or even touch the center electrode when checking cap . I used a .040 test wire that handily fit between the ground electrode and the center. I did this not to super accurately measure the gap but to make sure it was in the ballpark and not banged up so as to be above or below the factory preset gap. I will go over the connectors tomorrow by unplugging and replugging the connector to the igniter. I'd like to get a better visual look at the number 4 wire. It may be stressed at the bend where it needs to divert to connect to the #4 igniter connector.

 

I am using the mini-Vci cable with software from the car's port to USB connection on windows laptop running Windows 7 32 Bit Operating system. The program has been crashing frequently lately.. About a month or so ago I was monitoring misfires on the old beat up set of spark plugs and i believe they were in the neighborhood of 2-4 a week (of course I wasn't connected with VCI every minute of every time I was in the car driving. I believe the problem with misfires then was pretty well isolated to #2 and #4. Now I am seeing that many on a 15 minute run. Sometimes more. Like tonight I saw 2 on #2, another 2 on #1 and 1 on #4 (total of 5) . But like I mentioned, out on the highway after a good warmup, I didn't register any over a 15 minute run.

 

No plug wires were crossed. connectors 1-4 are colored Gray / Black/ gray /black.

 

Ill have a look at this too. Still odd timing that new plugs would bring on more issues

 

Now that you mention the throttle body and air fuel deliver issues, I checked to see what work was performed in 2012 on my front end by body shop after accident and the throttle body was replaced and the gasket using a "quality recycled parts" . The air filter assembly was removed and reinstalled for access (minclr). I also noticed when changing plugs that the top part of ignition coil #1 was written on with a white marker with the letters "#1". All this probably is not relevant but the throttle body is not original.

I'm thinking about fuel injectors as well. I'll going to dump a bottle of techron complete into the now almost empty fuel tank.

 

Riiiiight ?