First off an overdue apology: since I moved from CA to FL 4 years ago (drove all 3 Q's--one at a time) I know i haven't been hanging out on the board much.

Long story, but Q #3, the 97t and I are in ABQ right now.
1850 miles down and mostly trouble free (i did do a LOT of prepartory maintenance including vcg, plugs, ks, egr clean, full upper and lower plenum and tb clean).
yeesterday at a gas stop 90 min into the day's journey i noticed a bucking/misfire at idle in gear.
Offtopic, but did you guys know you can still buy ethanol free gas commonly in Oklahoma?)
smoother but slightly intermittent in park. no codes. I have an OBD II cheapo scanner with me and the ECU talk on the laptop.
o2 sensors bounce as I would expect, throttle V and MAF seem linear. running a consistent 190F.
also sluggish under part throttle until about 2000 rpm, then smooths out and has decent power.

made it to ABQ in part because there is the only Infiniti dealer for hundreds of miles there.
did pop a P0304 pending this morning
Had Garcia Inf do some diagnostics:
1st consult hookup (yesterday afternoon late just before closing), no codes, immediate item of interest was that the right bank timing control position sensor was reading 6-7 deg more than the left bank. Didn't do anything more, drove to motel.. took it back this morning, thinking that the cyl 4 misfire pending was the smoking gun (also got an pending P1125 TPS mismatch--note the TPS is set at 0.44v hot idle per Q-tech and verified by ECU talk). I did flag a P1125 near the beginning of trip, but no bucking symptoms associated.
tech first ohmed injector 4 and got 13 ohms.
then put o'scope on coil connector. Saw some weak pulses and mostly strong ones.
seemed consistent with me based on symptoms so I gave go ahead to change #4 coil (genuine 22448-3H000). idle very smooth in park, but as soon as in gear, bucking returned.
next was power balance at 190F, and cyl 1 showed effectively dead. I might should have asked them to run a second time, but i didn't. he ohmed #1 inj at the injector and got 12.5 ohms.
did then remove the snorkel and set up to probe #1 coil pak.
snorkel put back in place for test, saw some completely missing pulses when in gear and multiple missing pulses when in gear at ~1200 rpm.
THinking AHA! that must be it.
Had them order a carquest local coil (yeah I detest non-OEM parts, but.....)
1 hour later the coil arrives and he swaps it out and goes back for power balance.
this time power balance passed_ (note: 177F)
in order, the rpm drop from 1666rpm reference was
1-219
2-207
189
172
175
176
172
151

sensing that this needed to be verifed at full op temp, i had them run it again at 190F:
1710 rpm reference
-174
-139
-165
-153
-161
-157
-155
-149

not perfect but all within 20%--seems OK.
but the bucking is still there when in gear.

went for a ride with the tech to watch the consult: both VTC banks would go on and off at the same time (electrical signal) within the eyeball tolearance the cam phasing moved 20 deg on both intake cams --meaning the right cam is still showing 6-7 deg offset 102 deg with VTC OFF, and 82 deg with VTC ON. vs left cam at 95 and 75 respectively.
Had him o'scope the hall effect sensor for right bank (didn't do left for comparison), but the wave form looks consistent with page EC-256.
Both the tech and I were out of ideas at that point, so I decided to get off the clock and think about it.

my questions: does any one have similar cam timing readings from a VH41that is running clean?

OK guys--have at it

Jay

drove another 490 miles today.
Car feels solid on the road, but within 30 seconds after getting off the highway and at idle in gear, the bucking and misfire starts. also it doesn't stumble worse when i really get on it from idle vs. easing in.

ordered 6 more gen-u-ine coil pax today on overnight.

any other ideas?
Don't have a spare MAF unfortunately, but i do have one of unknown pedigree in transit for Saturday, hopefully.

I know on the KA24DE I would be telling everyone to look inside the camshaft position sensor for oil tracking. Not sure if the VH41DE is prone to this...anyone? anybody have a spare one? 23731-6P000

The big issue on the Y33 seems to be roving coil pack failures... I think you're doing the right thing swapping them all. I'm going to guess that'll cure it. I haven't heard of any common sensor issues other than the usual knock sensor failures.

Good luck!

Heath

thanks Heath.

we will see. at least coil pax I can do a field repair away from home and the major tools.And given the history of coil pax on these engines it is probably a matter of time anyway so it will be preemptive even if the primary issue is still hiding.
I may have to buy an el cheapo DVM to probe all 8 injectors at the sub harness for resistance.
It really *feels* like the MAF, but I can't correlate it to the ECU voltages I'm seeing from the MAF.
Maybe they are just low yet linear.

Jay
[edit] PS- the knock sensors (KS in first post) just replaced with the Nissan pedigree part.

UPDATE:
Completed the trip to SoCal, arrving Friday afternoon. an hour later the 6 coil pax arrived by fedex.
an hour and a half after that, the pax were replaced and she was running smooth.
had to wait a bit and do some drive cycles to get the ECU inspection ready.
Passed CA smog on first try Saturday.
Keys handed to my son, flew back to FL on Sunday.
A bit sad driving it for what will likely be the last time on Saturday, but at least it's still in the family and I'm just a phone call away....

I'm glad that fixed it! I hate to throw parts at a car, but the 97-01s that develop random misfire issues always seem to respond well to 8 coil packs and a case of beer.

Heath

I tried chasing failing coilpacks, but the best is just to replace them all with OEM Hitachi at once.