Took the lower cat assembly loose, took it for a drive, same results. Standing under it with the exhaust removed it was obvious that the rear cylinder bank was the problem. There was an audible blip, blip here and there, which I'm guessing was cylinder 3 misfiring. Looking up at the internals of the upper cats as it was running was also notable. The internals of the front cat remained grey/white and looked normal, however the rear bank upper cat was glowing red, which I'm assuming means excess gas flowing through it? I guess I'll go back to the injector/spark plug/wire/compression. Any ideas, I'm all ears.

 

I gots a B1 cylinder head sitting at home if it comes to that ...

 

more likely loose pins at the injector plug than a bad injector
sometimes when the plenum gets lifted to change plugs the harness will get caught and pulled causing strain on connectors ,have a very close look at the connectors and find a small blade to insert in the connector to see if it is loose, should be a slight drag on it, i use a small cotter pin that i have hammered flat for this purpose

 

Poor technique... where's your proper pin fit gauges ? Just shoving homemade items and flat blades is good way to goof the connector if it was not goofed in the first place,, use the proper tool for the job.

At minimum, the rainbow test lead set can be used for pin fit testing

 

in response sbr711,
how exactly would YOU suggest to test a loose pin?
im willing to bet in the same fashion , well probably bigjdog does not have a hyundai test jumper (rainbow) such as me and you, in which case i thought the purpose of this forum was to help enable hyundai owners with there vehicles.
i am very sorry that my post to bigjdog has some how bothered you to the point that you feel it necassary to question my competence and "technique"
i personally don't see any problems with making a homemade tool if the result is in finding the repair to said vehicle, maybe your criticism should be more oriented at pointing out to bigjdog that it is possible to damage a connector by driving something to large into it (which to me is common sense) instead of a personal attack on my "technique"
cyber-bullys such as your self are why so many techs avoid forums such as this ,
and if your purpose was to create some attention to yourself and your great mechanical profess you certainly grabbed my attention with your comments

i have removed my post as not to offend ,

 

Good news!! Problem solved. First though, I have to admit that I never actually switched the plug wires from one cylinder to another, I just pulled them off the coil packs, and switched posts to make sure spark there, and that the idle changed when each wire was removed from the coil packs. Ends up the plug wires on cylinders 1 and 3 were melting from the inside out. The only reason I could tell was that there was a small section of the hard plastic part that just looked like the casting was bad when it was made, but since none of the others had any blemishes, i decided to try and disassemble it. Gave a tug on the wire and it came right out of the top. The coating was all melted and the wire just crumbled when I touched it. So I also pulled apart no. 1, same thing, just not quite as far along in the decay process. I was told the wires only had 10k or so on them, so I never gave them a second look until I had exhausted all other options. Long story longer, don't use Napa Mileage Plus wires on your 2.7. I got a set of NGK wires this time, so hopefully that'll be the last I have to mess with it. Thanks for the help guys, I really appreciate it.

 

Very good..

Normally I try to sell new wire set with plug replacement.. that way customer can decline the added expense, then I get paid to replace the wires at full price (wires and remove intake)..

 

Yeah, me too, you gotta take them halfway off anyway. This car is a neighbor's, who's kid is a friend of mine and he's the one who put the plugs and wires on. When it started having trouble I only changed the plug in cylinder 3, since that's where the trouble code pointed me. Guess I probably looked at the problem ten times, without knowing it was falling apart from the inside out.

 

The OE Hyundai wires will show a tell tale discolor ring on the black plastic stick that sits over the spark plug.. if real bad "ala" Accent & Elantra, they arc right throuch the plastic with age, see a dry black dusty lightning bolt zig zag crack, with white and white blue color too.. they're done, time for new wires and fresh plugs. See it too occassionally with the 2.7

 

Here are a couple of pics of the bad wire. After I pulled it apart, obviously.