The Mystery of the Misfire

Wow! It's been awhile. Been surfing the threads again lately and I gotta say, I've really missed this community. Good to be back!

Here's my situation (similar to several other threads I've seen but with some unique variables):
It's a lengthy description but, I want to provided as much detail as possible as to not waste your time with unnecessary back and forth on basic info. I will bullet on the particulars to hopefully make things clear.
Thanks in advance!

Truck:
-'03 3.4l, supercharged (1st gen gray), 192k mi.(+/-), CA emissions, purchased from
original owner December/January 2012
- Supercharger serviced October 2013 (Jon Bond! https://www.jonbondperformance.com/ )
-URD supercharger (2.2) and tensioner pulleys added same time. (Tensioner pulley had
quick, i think, wear. hour glassed, destroyed my belt this past Sept. even after belt
adjustments. Replaced with old pulley. (2 years, really?!?)
-Lou's Custom High-flow muffler installed February/March 2014.
-Electric cooling fan
- Class III receiver hitch w/ BrakeForce module
-Deck Plate Mod (original K&N open CAI removed February 2014, OE air box w/ K&N filter
/deck plate installed) swapped K&N for dry filter one month ago) Run open when conditions
allow. "?"
-Came with URD chip, older module, had known issues with throwing codes after time, URD
released new chip to correct. I removed the chip in 2014. Never got around to getting
new chip.
-URD 6 high-flow injector and fuel pump kit.
-Always use 93 octane. On occasion, every couple oil changes, add injector cleaner or
octane booster, and maybe some Motor Medic flush (3,500 mi +/- change intervals)

Issue History:
-Fairly consistent, audible knock, with or without URD chip, since purchase. Conditions:
acceleration from below 2500 rpm, most typically in 4th gear. Never a knock code.
-A couple O2 codes over the years, typical. Tested. Failed. Replaced. Cleared.
-A few misfire codes over the years. apparent causes were coil packs, and found a loose plug a couple times. Always seemed to solve issues/clear codes.
-Winter 2016 some rough/false starts and idle noticed occasionally, fine on road (save the
knock) Later, codes for Cam position sensor. Test. Good. Clear code. Doesn't return. (New
England Wintah, kid!)
-Steering rack and lines replaced September 2016
-December, trouble starting and rough idle begin again. Then some stalls
after start. Then rough run on road. Acceleration gets rough. Lags and chorttles. Worse the quicker the attempt at acceleration. Smooths after very slow acceleration and/or higher rpm, 3k+
-Late December Cam pos. sensor codes again. Resistence test inconclusive. Truck runs the
with or with out sensor plugged in. Replace sensor. Clear code. Idle for ECM reboot. No
change in idle. Next day let idle again for 20 and drive. Codes for misfire #2.
-Coil 5 tests bad. Bad ignition wire-coil connection found. All plugs varying degrees of crap.
1,3,5 plugs better than 2,4,6. Clear arc marks on plug 2. Gum on the hex of many
plugs. One coil, and a couple boots as well. Consistent with loose or unseated plugs. A couple did seem loose. But again, 15ft lbs isn't much torque. But, it's spec. Replaced coil packs, all ignition wires and plugs. I was overdue. Makes sense. Old plugs were Bosch Iridium. Replaced with Denso OE double ground. Cleared codes. No change in idle. Starts consistently. Accelerates well. But, codes for multiple, 1 & 5 misfires.


-Double check plugs, wires. Clean coil secondary terminals, again.
-Swap packs forward 5 to 3, 3 to 1, 1 to 5.
-Cleaned and tested MAF. Circuit appears open/no reading when testing for resistance.
-Cleaned outer throttle body (intake port and plate. No gasket yet. Will remove TB and do
complete clean, IAC and TPS checks when i get the gaskets)
-Check, clean PCV valve. All good.
-Cleared codes.
-Start. No apparent change. Idles rough. Rpm start at about 1500 and drops to 500/550 by running temp. Sustains 1500 for a minute or so. drops, somewhat abruptly, to 11/1200. Then abruptly to 700/800, then to 500/550. Increasing that rate of drop as it warms.
-Watch the drive time with the scan tool. Confirms low idle speed. MAF initially low, 3 then in range briefly, then high. As high as 8, then fluxes to 5 and back, at oper. temp.
(4-7 is spec. although with supercharger, and with or without chip the values change a bit
but i'm not sure exactly) I can't remember fuel trim, off hand. All my notes are in the truck
atm.
-Drove for a few miles. Acceleration remains stable, except from stop. Need to rev up. Idle
still rough. But no stalling on cold start or warm stop as of yet. No codes as of yet.
-No codes other than the 2-5 misfire, the 1,5 multiple misfire, and cam. pos. sensor have
occurred.

The check list:
-MAF retest
-Run with deck plate open and see if anything changes.
-Throttle body, IAC, TPS. Throttle/accelerator cable, peddle etc.
-Triple check ECM wiring harness where chip was connected.
-Injectors
-Cylinder compression check.
-Fuel pressure. Fuel pump, filter.
.
.
.
-Get a new URD chip.

Looking for some direction here. Anything I should add to my list?
Any experience with similar issues? Any insight particular to 1st gen superchargers and 1st gen Tacos?
Going to take it on another run and do another, longer run time scan shortly.

Thanks for your time!

 

It seems most complain about long posts, I'm the opposite. The more info the better, and I have to say this is a very well written and explained post. I wish I had the answers, but thank you for such a well thought out and composed post. Makes it much easier for folks to help.
Have you tried a compression test, out of curiosity? Head gasket is good?

 

@cruiserguy
Thanks! I agree, I prefer more detail as well.
No, no compression check yet. No tool, at the moment. But, it's on the list.

 

The plug from #2, removed when misfire coded after cam. pos. sensor replaced. They all look bad, this was the worst. Makes sense due to being on the wire that had the poor coil #5 connection.

 

Was this one of the plugs that was loose ?? It looks like you're blowing some fuel past the plug gasket. My best guess is that the fuel residue on the plugs is carbonizing from the heat, and the carbon tracking on the plug (first picture) is what's causing the misfire. I think you should try using a torque setting greater than 15#s, since your effective compression is much higher than stock because of the SC. Maybe another member knows what spark plug torque TRD recommends with their blower. Good luck.

- JAMES

 

@JAMES399
Yes it was. It also had the bad wire. I agree. I tightened down to about 20# and plan to check them more often and adjust as needed.
Thanks!

 

Those are the wrong plugs, you should be using duel ground plugs on the 3.4

 

Agree 100%. If toyota recommends them, I would use them .

- JAMES

 

@757yotas
Yes, I replaced then with the Denso dual ground plugs, as I noted earlier.
Thanks

 

Typically guys running SCs are running cooler plugs (IIRC they're denso IK22). These are only available as single ground plugs. Which means you'll be replacing plugs on one side more often than the other side.

 

^agreed, stock plugs are too hot for the SC. Not sure why/if that would cause your issues, but if you're going to replace them, go with IK22. Also, torque spec for those is 13 ft-lb, and I wouldn't go much higher than that at all. I have stripped plugs out of the head from overtorqueing, it is aluminum after all.

 

You don't need dual ground but it looks like your gaps are way too large. IIRC stock gap is 41, depending on how much boost you're running you'll want to be as low as 30 and at least 2 steps cooler.

These are what URD recommends:
http://www.lceperformance.com/Spark-Plug-Denso-Iridium-IK24-5VZ-3-4-Liter-p/1084048.htm

 

Maybe check every inch of wires. Could be a small short.? Also did you switch octane level lately??? Just taking a wild shot.

 

Ah! o.k. Yes, I don't think the plugs are my immediate issue but, I'll pick some up anyway.
The pics are of the old Bosch Iridium plugs. The gap you are seeing is damage. That is not the gap they were installed with. Note: that is plug for cyl. 2. 4 & 6 looked about the same. 2 had the bad wire and appeared very loose. It's by far the worst. 1,3,5 looked better. Terminals were not rounded down. Still some gum and carbon though.
So... Denso IK22 or 24. What about NGK equivalents?
Thanks!

 

Every inch of the ignition wires, or all under-hood wires, or...?
Ignition wires are brand new.
No octane changes lately. I have put a bottle of Lucas octane booster in it two, three times a year. It may boost octane to 94 +/-. I use it because it seems to lower the instances of knock. Haven't used any in sense this past Summer.

 

My freeze frame data.
Coded while idling, just below oper. temp.
#1,#2 misfire with #5 pending.

 

(@fiziks , @drr , @Clay_916)

I'm going to replace the fuel filter since I'm under the hood anyways. Definitely has more than 60k on it.
It seemed odd though that with the URD 3.4l SC kit (6 injector, 190 lph fuel pump upgrade) that they don't have a high flow fuel filter as well.
Would a high flow filter benefit my set-up?
After I wondered about this, I noticed that they do supply them with the 4.0l kits now.

 

I would be curious to know the answer to that as well, perhaps @Gadget@URD could answer that. May have to give him a call though.

Don't spend too much time looking for the fuel filter under the hood, it's directly below your drivers seat

 

HA!
Yes, I was being figurative.