Okay, well the check engine light was on so I went and had the code pulled at Autozone and they showed two codes, P0123 & P0222, saying the Throttle Position Sensor is bad. I can see that causing issues with the 4WD since the computer uses the sensor readings for transmission control. However, I am still interested in any other input if anyone has any. They want $200.00 for that sucker. I have NEVER seen a TPS that expensive before.

LOL. Its entirely possible. Im in the process of cleaning the connectors now. Im going to pull the throttle body back off as well and just clean it out as well with the gunk it has on it from the EGR system. Im amazed that with the plug boots these things have on them that water could even get up in there and drown out a plug, it just seems nearly physically impossible.

Okay, I went out and did as you specified. I could not hear it engage either way, so I had my wife come out and work the ignition as you asked and I put my fingers on the TPS. I could feel it engage, and then a couple seconds after she turned the ignition back to the off position I could hear and feel it close. It didnt thunk close, more like it did it in a motorized fashion. After we did that a few times, started the vehicle back up, but its still idling the same.

The check engine light came back on after driving around a while earlier today after I cleaned the throttle body, but the 4WD warning light did not come back on. So I'll go have the code pulled in the morning and see if it points to the same thing. It idles just a touch rough and a little low. I can turn on the A/C and because that bumps up the RPM a couple hundred it smooths things out. There are no responsiveness issues, it takes off the same, shifts the same (as far as I can tell), the only issue is just idle when you are in park or at like a stop light.

I have an AllData subscription, but its not as helpful or informative as the other vehicles I have, but I did manage to pull the schematic for the TPS circuit and it shows two variable resistances for the TPS which is a bit unusual. When I tested the TPS, not knowing there were two, I only tested across pins 1 & 2 which only tested one of the variable resistances. It looks like both resistances tie into pin 1, then pin 2 is the wiper for one of them and pin 4 is the wiper for the other which I did not test.

Is it possible for one side to go bad and if so would it cause the issue with the idle? My suspicion is no. Ive had TPS's go bad before and it causes all sorts of issues with the idle, namely and in my experience run away idle (very high idle) and issues with transmission shifts, neither of which is the issue here.

The other odd thing I noticed today is that the gas pedal has a cable linkage to spring lever mechanism that is just behind the air box and there is a sensor on it as well with probably 6 or more wires and Im not sure what that is. But there is no physical connection from that spring mechanism to the throttle body. Normally, I would expect to see that mechanism on one side of the throttle body and the TPS on the opposite side. So whatever set up Hyundai used I am not familiar with. Is it possible that sensor on the spring mechanism is faulty and what is the name of that sensor? The only thing I see that even remotely appears to be that sensor on the schematic is the APS but I have no clue what that is or what it stands for.

Sorry for the long post and I appreciate the idea, hope you or anyone has more.

Well I went out and checked the vacuum lines. Though I put them back exactly as I found them, when I compared it to the vacuum line diagram for the engine off AllData, it did not match up. Keep in mind, I did replace the lines because I found a couple of them severely cracked and one with a hole in it, but below is how I found them routed when we got the vehicle:




There is a bracket with two metal vacuum lines. Only one of them was in use and it was from the EGR to what I believe is the EGR Solenoid (laying on the blue cloth). When I did the work of replacing the spark plugs, that solenoid was not mounted to anything, it was just kinda dangling back there. Also, there are four bolts on the back side of the manifold that apparently mount the manifold to a pair of brackets on the back side of the engine. None of the bolts were back there. I managed to replace two of them. The other two fought me pretty good so I called it good with two of them since it had apparently done okay with none of them there.

So it would seem that whom ever last replace or had the spark plugs replaced was kinda lazy in their work. I found a dangling bracket on the side of the engine where the serpentine belt is on the back side but could not get it to reach to any point I could mount it to and still get the egr solenoid to reach it. So I just used the threaded stud on the egr solenoid and screwed it into a vacant threaded hole on the back side of the manifold and used a locking nut to hold it in place and its in there solid and isnt going anywhere.

Back to the vacuum lines. I printed out the vacuum line diagram from AllData and took it out to the Santa Fe and routed everything according to how it shows it to be routed. That diagram can be found here:



After getting all that done, I started up the vehicle and its still idling the same. Seems like its about 200 RPM low. I did cancel the order for the EGR, so I can go back and order it again should it be determined down the road its needed. But for now Im out of ideas as to what the cause is. The check engine code says its insufficient flow. I dont know if I just need to pull the EGR off and clean it or what. I can tell thats going to be something of a chore as that main pipe that feeds the EGR, the nut that connects the pipe to the EGR is in a tight spot and Im not sure how Im going to get to it if it comes to getting it off to clean things up.

sbr711, if I done things correctly, you should have a message with my email address.

I went out and instead of applying 12v to the solenoid to see if it would engage, I realized with the engine idling and being a normally open switch it should be open at idle and should feel vacuum through the solenoid, so I pulled the vacuum line that leads from the E port on the throttle body to the solenoid and I have vacuum up to that point. I put that hose back on, and the other hose on the solenoid goes from the solenoid back to the bracket with two hard lines on it back to the A port on the throttle body. Meaning I should have vacuum on the hose side of the A port on the throttle body, and I do. So that would seem to indicate the solenoid itself is okay.

That seems to leave just the EGR valve itself if Im reading everything correctly. I wish I could get to everything easily Id just pull that sucker off and clean it up and see if that had any effect.