Hanky, it does it up any hill where I can duplicate and maintain the speed, rpms and throttle position, but I know exactly how to do it on that hill and the location on that hill where it will start kicking. It can get violent sometimes if I let it go that way.
Aquanaut20, the coolant pressure test lays evident in Lowes parking lot! :D I'll refill and search for the source of the leak before digging in.
I have a test plan for the EGR. Let me know if there is anything not noted where I should be concerned. I hear this procedure is confuser delicate (like destructive) if done wrong, so I would like some reassurance on it. I don't need to buy a confuser too!Your comments are welcome.
Thanks.
Curt.

Well, the results of the test: With all prior tests passing, test #6 failed. The control pin never came off of 1V when grounding the solenoid. By what I've learned, this indicates a DPFE sensor failure, so I guess I need a new one.

Hanky, I've taken a datastream with the engine not running to get the cold temps as you requested. In it I noted the coolant @ 37F and Intake @ 42F. This was done around 1pm today and it was warming up nicely outside, so I can agree with those numbers. What puzzled me was the throttle position @ 16.5%. I never touched the throttle since before I turned it off yesterday and before taking the reading today. I don't know if that's normal or not without doing more research, but it seemed high to me. One more note about reproducing the engine kicking. I've noticed that in order to get it to misfire, the load has to be kept constant and maintained for a few seconds before it will start to miss and so long as it's maintained, will miss frequently. Up or down a few rpms, move the throttle or go outside the speed range like cresting the top of the hill and the miss stops. I just wanted to clarify that from my last post. I don't know if the DPFE will do this or if there's a throttle position control issue, but I'll fix one thing at a time and see what happens!.

So far as the coolant discharge yesterday, I refilled the reservoir and warmed the critter up for the EGR tests, drove it around and climbed some hills, but no steam! I don't know exactly where it's coming from, but it is wet from the rear head around the left side of the water pump. This i noted before starting the vehicle, and it didn't seem to get any wetter or drier after I was done. There was wetness around the lower vent port on the water pump, but it's also on the rear head side of the pump. The top port was bone dry, which is making me lean toward a head gasket or something outside the pump, but I don't know at this point, and the water pump is beyond the scope of this thread. I am not getting a coolant smell from the exhaust either. I'm miffed!

Thank you both for helping me through the diagnosis process. I guess the new shade tree mechanic has to carry a computer around with him now! :D I'll post back when I get the DPFE sensor replaced and let ya know if that fixes some of my problems.

Curt.

Update:
I have replaced the DPFE sensor, reset the codes and have driven the vehicle a few times. Today, I read the codes and no P0401 code present, but now I have a temporary P0136 - O2 Sensor Circuit Bank 1 Sensor 2. In looking for a possible head gasket coolant leak, I also discovered that I have an exhaust leak somewhere which I have read can cause this code to post. More fixing! I also found that there is no coolant in my exhaust or in my oil and have learned that the timing chain cover gasket is a more popular coolant leak cause than the water pump for these vehicles. I have not experienced another rapid loss of coolant since the Lowes trip. My cooling system pressure check kit arrives tomorrow. What's more, I can no longer reproduce the strange engine miss/kick with the combination of conditions anymore, and that has been since before the DPFE replacement.
Thanks for putting me on the straight and narrow - test, diagnose, then repair! I learn more through patience, spend less in parts and get more cool tools!

This is a circuit code, check the wiring first, chafed, burned..

As a final post, I wanted to update the status of the DPFE sensor replacement. I have just recently checked my codes again after a month of driving around, and to my surprise, there were none present, not even the P0136, and I have not experienced that "kickback" since as well. With that, I'll assume it's fixed for now. The coolant leakage is still status quo (not leaking) and is better suited for another thread.

Thank you both again for your assistance, patience and expertise in guiding me to repairing this problem I have been having for years.

Curt.

Thank You for the update.