Read all the P0171 related thread, most are E39, with no shining light, yet. Here is the chronology of my case:
Started the car and headed into town as I normally do and about 4-5 minutes into journey the engine malfunction message illuminates and check engine light came on. It was into a limp mode with reduced power.
After stopping the car at first location, about a five minute stop, it fired up and drove essentially normally except for the check engine light illuminated. A little while later I received increased emission message. Upon return home, I plugged in my Innova 6100P code tool and found P2177 and P0301, p0302, p0303, p0304, p0305.
Hmmm, I say to myself... No way did all five plugs, coils or injectors all go bad simultaneously. So I think possibly the MAF.
I reset the code and swapped the two MAFs. The problem presented itself again still on Bank 1. So, I think I can eliminate bad MAF (not positive but think so). Now I start to wonder about this and find another MAF close to the secondary air pump. After replacing that, no changes. Still getting P0171 and the five misfires, and now I've also snagged a misfire on 6 and 10.
On the next drive I get messages again, and this time I have my code reader with me and I get P0112 IAT range. This P0112 has not come up again, only that one time.
I verified the secondary air pump is working. Checked the connection of all possible vacuum leaks I know about. The two breathers at the back of the plenum are connected. Checked to see that the brake system is holding a vacuum, as I did disrupt that system a few weeks earlier to replace the master cylinder. Maybe a smoke machine to look for vacuum leaks?
Next drive she runs a long time before giving any message, but they come. This time the code soup included P0101 and P0420 and 0430. The last two are catalytic converters out of range, so now I am concerned even more that some simple problem could cause high dollar mpact.
Hopefully someone out there will see this and either point me to a culprit or an expert.