Hello friends, I am so grateful for this community and all the help I get without having to ask a thing

Today I need direction on codes that I have read much about here on the forum, but my context is different than the posts I found.

2003 XJR, I had to change my coolant hoses that run under the supercharger. That job went smoothly using articles here and the JTIS. I replaced some but not all of the gaskets. I reused the one between the throttle body and the SC intake elbow, and I reused the two gaskets on the EGR - the one from the brass pipe to the valve, and the one from the valve to the intake elbow. (During reassembly, I removed my EGR from the intake elbow so it would be easier to maneuver when threading those 4 tricky bolts to the SC with the new metal gasket.) I had needed to clean my EGR 2 years ago, so I reused those gaskets thinking they were "made of metal, and relatively new, and not super critical." (Of course the one from EGR to intake elbow is not metal, but it appeared to be in very good condition so I went with it.)

Car starts up fine, no coolant leaks, no known vacuum leaks, sounds perfect. 15 minutes into my first test drive, I ended up with code P0405, EGR low input. I opened the hood and saw that I hadn't plugged the wiring harness back into the EGR. In the entire engine compartment, was the only loose end that I appear to have missed during reassembly. I plugged it back in and the code went away.
On return from that drive, I knew I also had dropped a little hose clamp on the vacuum line that goes to the MAP sensor. I had reattached the hose to the sensor but I didn't love how the clamp wasn't on it, so I was able to find the clamp on the ground where I had worked on the car. While the engine was running, I pulled the vacuum line from the MAP, attached the clamp, and fitted it back onto the MAP snugly. I could hear the vacuum in the line loudly when detached.

A few days later I was driving the highway and the MIL turned on again, this time showing the EGR again and the P0172 & P0175 rich mixture. I'm also getting the intermittent "Restricted Performance" message where it doesn't seem to affect most driving conditions.
I came here to research, and found many suggestions for P0172/5. I cleaned the MAF, I've read all my real-time statistics to ensure my engine coolant temp, MAF & O2 sensors seem to be working. Air filter is gucci. I'm sure I don't have new leaky injectors simultaneously in both banks. The plastic PCV pipe from the valve cover to the main air intake tube has a little damage on the clip at the intake tube, but it does seem to seat properly. I plan to put a little grease on that fitting today to ensure a good seal, as was suggested here in a post.
All of this seems like it could be tied to the EGR. I can't find any lines or sensors that weren't re-attached correctly, and I had no question about my vacuum routing because I took good notes & pics during disassembly.

My main questions to you are
Do you think the rich mixture is related to the EGR low input P0405?
Do you think I may have damaged my MAP sensor when I pulled the vacuum from it and then reattached while the engine was running? I suspect there must be a diaphragm in there... maybe I ruptured it? Would a bad MAP throw any of these codes?
Do you think I may have damaged my EGR valve by driving without it plugged in during that first drive? I don't know if it being closed (or open?) when it's not supposed to would screw something up... thinking "heat".
Do you think I may need to simply get new gaskets for the EGR and possibly the throttle body?
Do I maybe just need to disconnect the battery & touch its cables together to get the ECU to reset and figure out the mixture again?
Any other thoughts?

Thank you for your time, I would be completely lost without all of you - on every repair I've ever done!
I have attached screen shots of what I get from my scan app (I use one of those bluetooth OBD connectors to my phone).



This was from the freeze stored in the ECU. I can get additional real time readings if needed.

 

I usually re-use those same gaskets and have never had a problem, but will probably replace them the next time I'm in there. For the EGR problem I would check the torque on the pipe nuts just to make sure that you didn't forget to tighten those.

Those Short Term Fuel Trims are way out there at -25%. That means the ECM is supplying 25% less fuel than necessary for optimum air/fuel ratio. Check the fuel pressure; it will probably be high. If so, it's more than likely the fuel pressure regulator. I had that happen a couple of years ago.

 

Thank you Mark!

I don't know what changed, but the P0405 went away on its own 3 days later, and then the other two as well the following day. The MIL is off and I only wiggled the wire going to the EGR valve to make sure it was securely attached.
However, your insight about the fuel trims and the pressure regulator is very helpful and I'm looking into testing and replacing if needed.

Thanks again, I'll write more here if I learn anything helpful to the group.

 

Just in case, did you re-attach the vacuum hose from the FPR to the port on the supercharger cover (marked on the picture)?

 

TNM,

Here are a couple of good articles on fuel trims and EGR valves. I've attached the fuel trim info and the EGR stuff is HERE.

 

stuck open egr only causes rich conditions on a map based car.

on a maf car it's unmetered air

 

Based on the OP's story, I don't think the EGR is causing the problem; wouldn't a P0400 code show up if it was stuck open? I can see why a MAF based car would increase the fuel ratio due to more air, but his STFTs on both banks is -25, meaning it's trying to reduce the fuel to meet the amount of air coming in. And, -25 is a pretty high value.

 

It's winter: all too frequently the temperature sensor in the cross over pipe goes bad and the ECU is not able to tell if the engine is warmed up; so it enriches too long -- or -- it thinks the engine is warm when it is cold. Check the temperature on your reader.

 

That's a good point, Jim. I've noticed some strong vapors from first start of the day, and it seems that it's taking longer for the idle to settle down to the 650rpm. That was during the summer. I would expect something like that today since it's 20F at 0800. Supposed to warm up some next week, like overnight lows in the mid to upper 30's instead of mid to upper teens. I'll hook up the scanner and see what it's doing then.