Hello, and thank you for your time for reading my post. Here is what's going on at the moment, i'll list my troubleshooting steps below as well as car history.

Platform: 2003 VQ35DE

Current Symptom: When i turn the car on it's throwing a P0102 Code (Mass or Volume Air Flow A Circuit Low Voltage). The car idles extremely rough, and will dip down below 500 rpms at times. It will come close to stalling and has stalled multiple times. It does this on cold and warm start. The car will also shut off while driving - even while accelerating. The car has been running fine for over a year and this symptom just appeared out of the blue.

Troubleshooting steps i've taken:

• Reset ECU - disconnected battery for over 12 Hours
• Checked Vacuum Lines
• Removed and Cleaned Throttle Body
• Removed and Cleaned MAF
• Performed Throttle Body and Idle Air Flow Relearn Process - Multiple Times
• Cleaned MAF Connection with non corrosive electronics cleaner
• Inspected Harness for any short circuits - i couldn't find any noticeable short circuits, but the only way i could really test this was to bend and jiggle the harness throughout it's path to the ECU to see if any wires were touching or contacting each other. I did find a loose ground on the front of the crank case that seemed like it was definitely the issue as it would cause the engine to die out when it became loose, however i reseated that properly and the issue is still there
• Replaced the MAF - i replaced the MAF with one i got from auto zone (i know, probably not a good idea but i'm simply trying to troubleshoot at this point)
• Mechanics Help - a friend of mine who has been a mechanic at a local dealer for over 20 years has been assisting me and has mentioned that it could be an ECT sensor? but i researched this and it doesn't seem like it would be that.

Car history:
I purchased the car from an auction a little over a year ago. The car was in pretty rough shape, but it was a good price for only having 68k on the odo. i've replaced most of the body panels and bumpers, it was also missing the entire plenum/tb assembly when i purchased the car. i've pieced the car back together by purchasing new and used parts. After getting the car running it has been solid for about a year up until this issue just occurred.

Known Performance Mods:

• Cold Air Intake - has been on the car for the year that i've owned it and has been working fine
  
• HKS (believe it's replica) true dual exhaust

Once again, thank you for all your help and any inputs are appreciated!!

 

I know opinions vary, but I'd stick with OEM parts, especially on the sensor end. I've been screwed too many times going with aftermarket components.

Using a live scan tool, what's the voltage reading that the MAF sensor is sending to the ECU? That should tell you quickly if that part is bad. You can hook it up to a scope as well and measure the voltage against a known good wave pattern.

 

Yeah I guess a multimeter on the harness should reveal any shorts or low voltages. I wander if the manual will show me that much detail as far as what colored wires output what voltages, etc. the only other thing I think it possibly may be is cam position sensors. However my slip and vdc lights are not on.

 

If you have > 80k miles on the car, I’ll bet the problem is the camshaft and/or crankshaft sensors.

I would read codes with two different devices to test accuracy.
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Also... as Zakmartin suggests.... Install OEM parts (sensors in this instance).

 

The car has 70k almost on the dot. I'm just so unsure. I hope to test voltages with a multimeter soon. Assuming I can find the correct voltages in the repair manual.

 

^^ You discover the problem’s cause by connecting the car to a Consult and reading the codes.

 

Well. Interesting things happened today. Upon resetting the ecu again last night and reconnecting the MAF is now reading 200+ g/s of air flow! Which would mean the car is basically falling out of s plane, lol. After re-seating the connector on the maf and even tapping it a bit it then started reading good airflow readings again. So my mechanic that was with me at the time refcommended replacing the maf connector. We used a multimeter and tested correct voltages to the wires, however the pins on the maf may not be seating properly in the harness.

 

Good end result! Thanks for the follow-up.