'97 Lumina 3.1 V6 "interrupted acceleration"

Here's an example of one of the "printable" moments that the Foxwell recorded, there are well over 50 pages: Calculated Load Value(%)14.9 Engine Coolant Temperature(øC)93 Short Term Fuel Trim -Bank 1(%)-6.3 Long Term Fuel Trim - Bank 1(%)-2.3 Intake Manifold Absolute Pressure(kPa)71.0 Engine RPM(rpm) 1893 Vehicle Speed Sensor(km/h)20 Ignition Timing Advanece for #1 Cylinder(ø)-1.5 Intake Air Temperature(øC)51 Air Flow Rate from Mass Air Flow Sensor(g/s)36.42 Absolute Throttle Position(%)43.9 Location of Oxygen SensorsB1S12--B2S---- Oxygen Sensor Output Voltage Bank 1-Sensor 1(V)0.045 Short Term Fuel Trim Bank 1- Sensor 1(%)-3.9 Oxygen Sensor Output Voltage Bank 1-Sensor 2(V)0.105 Short Term Fuel Trim Bank 1- Sensor 2(%)N/A OBD requirements to which vehicle is designedOBDII

Just test drove her again and got the error code: PO102 Mass of Volume Air Flow A Circuit Low I replaced the MAF a few days ago. So I remeoved the new plastic one and replaced it with the original aluminum one (that's clean as a whistle) and there was no change in the error code. Plus, I then tested it with my multi-meter, here are the results: 1) With the harness disconnected and the engine/ignition off: All three wires (red, black and yellow) ohm-ed out as ground. 2) With the key in the ignition and it turned to run position without the engine on: The power wire (red) had almost 13 volts, the ground (black) wire was grounded, and the signal wire had about 6 volts. 3) With the engine running and the harness attached: I tested the Hertz with my TEST BENCH set to 20 Hertz and the signal wire (yellow) had a fairly consistent 2.14 hertz at idle (engine warm) and when the engine revved it smoothly went to just above 14 hertz and then evenly went back down to 2.14 when the idle was slowly released.    ​​​​​​​So it seems the original MAF is working within specifications?

To add to my complex testing, I ran the car with my Foxwell attached and the Foxwell has a (g/s) reading for the MAF during the events in real time. It seems it was registering 4-5 during idle and was at the 40-50 range when it was bogging down, but when it cleared and accelerated as expected, it was well into the high 60s and into the 70s. Is this something that assists? Both the original GM MAF and the new replacement AC Delco MAF are performing the exact same way.

I found the yellow sensor wire that goes from the MAF sensor to the PCM wasn't clean when I used my Ohm meter, it showed about 1.71. I ran a new wire along the same route and spliced it into the existing connectors. The new test drive was markedly better in acceleration and speed. However, after clearing the code, it still showed ""PO102, Mass of Volume Air Flow A, Circuit Low." I grabbed an older laptop in great condition with XP on it, so I could run the GM program to flash the PCM, I'm loading XP Professional on it with Service Pack 3 so it should run it properly, and I'll "flash" the junkyard PCM first to my daughter's VIN and see if that fixes the issue. Sound Like a good plan?

It seems the PCM has the most updated software, and I cannot flash it without a Tech 2 scanner (which I don't have), but all I can do is check its values, and if I want, I could modify them like a fool, if I wish. Not gonna do it. I drove her again and found these three details quite illuminating: 1) In order to start it, you must push the pedal (open the air valve), or it will simply spin the starter/engine; which I don't think is how this car is supposed to start, ie. it should be simply to turn the key. Correct? Why do you guys think this little detail occurring? 2) But once it starts, it idles well and drives with all the power one would expect. 3) The "service engine soon" light is on and my Foxwell tells me the same old code, "PO102, Mass of Volume Air Flow A, Circuit Low" even if I erase it, and then drive it again. This is a new sensor wire as well as a new MAF. As an aside, something keeps telling me the original MAF is still good. As an aside, I had a friend tell me to disconnect the battery for a while, then reconnect it as this would allow the flash memory to be erased and the code might go away. Ever heard of that?

Finished (though I had to go to a shop with a Tech 2 and basically rent it with the mechanic). Everything is factory spec, and it idles and revs without issue. No trouble codes. Everything is within spec. when we looked over all the info in his Tech 2 readings. When driving (though markedly better and gets up to highway speed great), still it seems the engine, as it is accelerating: feels that it either adjusts the fuel/spark a bit, or the transmission shifts prematurely into a higher gear or something (that's the only way I can describe it). It's weird to feel the car do something without driver input. Whatever it is is keeps the car from continuing its acceleration for a few seconds. If I give it throttle during the event, it downshifts and accelerates great through the issue. If I don't alter the accelerator, and keep it steady during the event, it waits a few seconds and then shifts to overdrive and feels normal. Since I changed the fluid and filter when I first was alerted of the issue by my daughter during my maintenance work, and the old fluid was discolored (aged) and there was no metal dust or filings on the magnet, I'm wondering if I just need to allow her to drive it and change the fluid again in a few days and see if it flushes more of the old fluid that was trapped inside the torque converter?

Though no one attempted assistance on this forum, I have figured out the issues and solved the problem, and share it here: PROBLEM SOLVED So my friend has some awesome equipment to test Hz and other sensor feedback and we looked at the Knock Sensor and the O2 Sensors (much more sensitive than mine as well as had the exact ranges of signal that should be expected). The Knock Sensor and the O2 Sensors both looked slightly out of spec, enough to do a test drive with first the Knock Sensor disconnected and then a drive with both the Knock Sensor as well as the upstream O2 Sensor disconnected. With the Knock Sensor disconnected the drag or delay in acceleration under load was gone, though it wasn't completely smooth. With both disconnected, it drove really well and there was no drag or delay or alteration of power during driving. I replaced both the Knock Sensor as well as the upstream O2 Sensor and tested the car again. It drives as it should. So, in the end, the car had these issues: 1) the #1 cylinder had a head gasket leak, fixed with head gaskets replaced 2) the MAF sensor was sending inaccurate info and had a damaged wire, replaced 3) the vacuum Transmission Modulator was broken, replaced 4) the upstream O2 Sensor was not within spec, replaced 5) the Knock Sensor was sending wildly inaccurate info, replaced Interestingly, only item #2 above was determined by the PCM to be in error and would throw a Service Engine Soon light or throw a code, the PCM was silent on the other errors. I guess a '97 GM PCM was not very sophisticated. Anyway, thanks for your help!!!

I just want to say God Bless You to ClanofWolves. I just got a 99 w new head gasket job but with bad engine mount and what I found to be a VERY odd symptom (exactly as he detailed) Watched values on Scan tool and had P0300 and P0171 (the upstream O2 sensor) Haven't had time to figure this out and bless you for revisiting to post your findings and solutions. Very Concise!! I WOULD HIRE YOU IN MY SHOP (Im a service writer at a heavy duty truck repair shop)