[FIXED]2008 Nissan Sentra 2.0-Cam/Crank Waveform

(Original post I accidently deleted during edit after fix): Can someone help me out with a good cam/crank waveform? I'm a DIYer trying to fix a family member's car. Thanks.


After fix:
Vehicle was intermittently stalling at idle, misfiring at times, P0171(4 cyl, 1 bank), and P0300 random misfire DTCs. Initially suspected CKP, ignition, or possible timing issue. Made the mistake of going for the scope first before carefully analyzing scan data. Chased my tail for two days before I even bothered to look at fuel trims.

Snap on factory data was not giving me fuel trim/loop status, so switched to OBD global. Fuel trims were at 55+ or more and vehicle was going into Open Loop Fault roughly every 25sec, causing vehicle to bog down, misfire, and sometimes stall (the original complaint). Vehicle recovered after 5sec, returned to Closed Loop, ran ok, and cycle continued. Either ECU was going haywire or faulty somewhere was causing this. Test drove vehicle, AF ratio o2 looked ok, dwnstream o2 was reading very lean. O2's read rich at WOT but not as rich as I'd like (dwnstream read average of 700mV). Fuel trims improved at WOT.

Smoked intake, found badly torn intake tube, replaced. Fuel trims improved but still at 45+. Reset Self-Learn, no change. Test drove vehicle again and noticed intermittent positive fuel trim fluctuations. Scoped MAF sensor, snaps showed average of 2.7v. Checked sensor ground, ok. Removed MAF and sprayed with electronics cleaner because it was dirty. Test drove again. Some fuel trim improvement but still intermittently fluctuating positive. Reset Self-Learn, trims still no good. Removed MAF sensor again and grabbed a flashlight to take a closer look.

Found a dead fly rolling around in there. Got it out, lightly scraped resistors with small screwdriver and sprayed it. Immediately, fuel trims started correcting and Open Loop Fault cycle stopped. Symptoms were gone, too. Test drove it, fuel trim was still learning but looked good. Reset Self-Learn, test drove again, fuel trim was now near perfect. Fixed. Stupid fly!

Here is a 2007 2.0 if found on iATN.

(