So it looks like I've come through my slow loss of coolant situation in my 2001 GP SE, after treating the coolant with Blue Devil sealer - everything is working fine in the coolant area, have only added a tiny amount of coolant since the treatment a few weeks ago, a dramatic improvement.
Now I am dealing with an issue that was starting to develop before the leak issue, but has gotten worse in the last couple of weeks - a bogging/lack of power when trying to accelerate, which seems to happen only shortly after the engine has come up to temperature, and then eventually on a given drive, seems to go away,and the engine behaves normally - until the next time the car is driven from a cold start.
The problem is very repeatable, happens like clockwork every day on my drive to and from work. I will start the car, let it idle for a minute or so, and then drive off. In the first few minutes/miles before the engine fully comes up to temperature, it runs normally, and accelerates strongly and smoothly through the gears on local two lane roads that include several long uphill pulls where I am in 2nd to 3rd gear in the 20 to 40 MPH range. About 3 minutes from starting out, as the engine temp gauge comes up and settles around 185, acceleration through the lower gears, even on level ground, starts to feel boggy, like the car can't get out of its own way, its especially noticeable on a long straightaway with a very slight upgrade that I drive on every morning. It's sill slightly boggy as I accelerate up to speed for a run down I-95 for about 15 miles, gradually the boggy acceleration goes away, and by the time I'm off the interstate and back to going up and down through the gears on local roads again, the engine response feels normal.
The same problem repeats itself on the trip home, from a cold start the engine initially feels fine and has normal power. The point at which it gets boggy a few minutes after cold startup after the engine comes up to temperature always occurs just about at the point where I am getting on the I-95 North bridge from New London to Groton, its a long fairly steep uphill pull and the lack of power is really bad there when I am coming onto the bridge at about 30 mph. By the time I crest the bridge I can work the speed up to 65 and can maintain that or more all the way home, and when I am back on the last few miles of the trip over hill and dale on local roads at low speeds, the power and throttle response is normal again. When its at its boggiest, its at its worst when trying to get through 30 to 50 mph range in 2nd and 3rd gears.
I generally am not throwing any codes from this. When the bogginess does occur it often feels like it is rapidly cutting into and out of normal power, but no misfire codes so far. I have tripped a very occasional P0404 EGR valve response code, when this has come in (only 3 times or so) , it happens after I've really tried to goose out some more acceleration with a mashed throttle downshift.
I'm suspecting this might be due to bad plugs and wires (at 94K and I am fairly certain its still on the originals of both). I have had similar types of issues like this on previous vehicles due to really worn plugs or wires, but they usually happened all the time, and did not come on go so regularly during a daily driving cycle. Going to put new plugs and wires in this weekend. I wonder if I am missing something else that might be causing this unusual repetitive problem?