Oil level should be OK; I recently changed the oil but will check anyway. Haven't checked MAP sensor for oil; I'll do that today. I believe you're right about the slight incline and low boost when the stumble and loss of boost occurred. I was just cruising along maintaining 65-70 MPH just before my exit. That slight incline was right after a slight decline. So, How is the incline/low-boost related to the problem? Any insight much appreciated...

Just as I was about to trust the car again...

 

My oil level is good, but I will check my upper map sensor for oil. I know my lower wiring is good as I checked it thoroughly. The latest problem was at steady highway speed making about 1psi of boost. Is this relating to the upper map sensor covered in oil?

 

I would take another look at your lower tmap wiring. I cut out the crimps to solder and heatshrink the wires. (i think you already did this) But I also dremel'ed the lip off my hotside pipe so I could flip my lower tmap to face toward the radiator. ALL of my issues went away and have been gone for the last 3000 miles.

 

I agree with the 180 turn of lower tmap sensor
It eliminates any chance of the sender getting hit or the wires.
I had a bad pcv valve in mine that was causing oil to get into the intake

 

Well I cut out the old solder joints, and re soldered and heat shrinked the wires. ground the tab down and turned the sensor around. Cleaned both map sensors, although both looked very clean already. I erased the pending dtc and reset the keep alive memory. I only put on 30kms today after and it seemed to run alright, time will tell as it is a intermittent problem.

 

You turned the lower sensor 180 degrees without moving the lower radiator forward?

 

I didnt have to move my radiator forward at all. I had enough space. There is a little dimple in the radiator near where the sensor mounts that provided just enough space for the wiring harness.

 

400 miles since I cleaned the MAP and MAF sensor with no boost issues...until yesterday. Just off the interstate coming to stop at the signal light I felt a slight stumble/miss. No boost upon acceleration from stop light to stop light for two blocks. Then the boost miraculously came back to normal shortly thereafter. No check-engine light, but I haven't checked for pending codes yet. So, here we go again. Just about the time I start trusting the car again, the boost problem rears its ugly head. :-(

UPDATE: Just scanned and found Pending P0101.

 

Oil on the upper tmap sensor?
Any oil film visible down in intake

If not guessing i am betting boost leak
Or the lower tmap wires are getting moved enough or hit enough where there is a mild or noticeable crack if inspected closely.
Was it a rainy and or humid day?

 

The MAP sensor was pretty oily and dirty before I clean it on 2 Sep. Ran good for about 400 miles.



I thought the intake looked pretty clean on 2 Sep. There appeared to be a slight film of oil from what I could see through the opening where the MAP sensor goes but nothing alarming to me.

Another update from today (23 Sep):

During short trip from home, car ran good. On the way back, came off the the interstate, no acceleration pulling away from signal light (felt like it was going to stall right in the middle of all the rush-hour traffic), but it finally got enough power no boost after playing with the throttle to make it home. No CEL but had Pending P0101 and Pending P0556 (a new one for me). About 1/2 hour later, took the car out again. Ran good for 1/4 mile then same no power, almost stalled, no boost but a CEL this time. Checked with scanner after I limped home--CEL=P0101 but Pending P0556 went away. I think it's about time to take it to the dealer or set it on fire...

UPDATE (24 Sep): Checked upper MAP sensor--looked cleaned and oil free, but cleaned anyway. Cleaned MAF sensor. Rerouted lower MAP sensor wiring. Ran like a rocket during test drive--easily produced over 15 lbs boost just rolling into 1/2-3/4 throttle like it should all the time. We'll see how long it takes before the boost goes flat...again.