2005 bangs only when charging

Hi! New here, sort of. Drove Gen II's as cabs and medical transport cars for about 4 years, lots of miles. So, I've popped in now and then to help sort minor issues. Now, I've got one for personal use and it's a gem. 257K, and used for the past 5+ years on a very country gravel road. It was absolutely filthy when I got it, if you are a Gambler 500 person, think the OG. It was covered in moon dust, inside and out. Regardless, it was generally well maintained and aside from being rather ugly, it's been returning about 40mpgs.

I did all sorts of searching and have not found this particular 'case file'. I'll describe what I'm seeing and perhaps someone has a link to an existing thread, or can direct me where to go from here.

1. A month or so of wonky no-starts. Discovered it had a recent 12V and it wasn't installed correctly. Fixed that.
2. Drove the car a full day after the battery correction, no issues.
3. Started the following morning, and BANG BANG BANG, I immediately suspected a coil pack.
4. Purchased one coil pack, and walked it across all 4 cylinders, resetting the DTC each time. No change.
5. Changed all the plugs. No change.
6. Codes pulled show 301. Put the new coil pack on cyl 1 and left it there.
7. Verified wiring to all the coil packs and the injectors (all good).
8. Cleaned the MAF (with the correct cleaner). No change. Cleared codes.
9. Full can of Seafoam in the tank, 1/2 hour idle with intermittent 'restarting the ICE' tricks (shift into D, turn up the heater fan, etc.)
10. Drove it 20 miles. Engine was obviously misfiring at intervals, sluggish below 25mph, really boggy at 55. Flashing engine light off and on a couple of times, then hard on. Stopped at mile 10 for a turn around and pulled codes. Seven 301's, cyl misfire 1 & 2. Cleared codes.
11. Some improvement (which I'm attributing to the Seafoam), on the return run, but more misfire codes.
12. Checked and cleared codes in the driveway, noticed the engine seemed to be running much smoother, the BANGING was very intermittent. Turned on the DLC info and watched, the banging ONLY happens when I have a green arrow to charge the battery pack.

On a couple of code clears I got the red triangle of death, but I was able to clear it after 3-4 restarts/moving the car in gear a bit. I'm using a Zurich ZR8 OBD2 scanner.

So, injectors?

 

Thanks JC. Here's what's got me confused: I put the car in P-N-P gas only mode and ran it up to 2500 in the driveway. I used the real time feature on the OBD scanner, to monitor it. No banging. I was expecting a 'limp' mode, or some sort of limiter to kick in if the car was throwing misfires, but I didn't see it. No faults until it began with the green arrow->battery charge. It only bangs in this state, but obviously it's still not running properly. With all the switching back and forth gas/elec in D, it's affecting performance and mileage.

I'm ridiculously poor, thus the one coil pack. Weather in the PNW is a bit crazy this week, so I decided to buy a warranty part at O'Reilly's rather than brave the yards. If it continues to act up, I'll have to spring for injectors, and I was attempting to sort of split the problem. By testing what I did, I think I've narrowed it down to injectors.

It's the load part of the equation that has me scratching my head. Why does it only misfire with the electrical motor/battery load?

While not Toyota level, the scanner does return 36 different measurements on the car. I don't know what most of them mean, perhaps there is a specific indicator I can examine when it changes state?

 

Thank you, I'd read this thread. Don't have a really good place to work on the rig, but I believe I might be the guy to get these off your shelf. Payday is Friday, I'll check in with my mechanic. He's very good with these cars, and he's got the Toyota software. I'll see if I can get a diagnosis from him and try to decide what's next. His rates are really good, and he was my old taxi mechanic, so we have good history.

Been a gearhead my whole life, and it took me several years to openly profess my love for the Gen II. It's an amazing bit of ingenuity. The appeal for me is the level of sophistication that's not apparent to the end user. Very Japanese and nearly elegant in it's execution. It's not a Buick GS455 or an Impala SS, but I couldn't afford to feed (or insure) one of those these days any way. The Gen II strikes me as having just a bit of '62 Thunderbird in the lines, particularly the side profile. Maybe I'm nuts, but I pretty much adore this car.

 

Just ran a quick errand and the 'check engine' light is back on. I noticed an interesting development though.

While warming up the car, it started with a bang and ran that way for a few minutes while charging the traction battery. I recalled an issue we had with the cabs, in that the Park detent would allow the car to roll a bit. A big no-no for a commercial transport rig. Our mechanic (same guy I still use) did something to the cars to correct this. I believe it was a rather simple adjustment somewhere.

Anyway, I put the car in D, let it move slightly, kept my foot on the brake and put it in P. No banging. Still a bit of rough idle, but it is improving (Seafoam).

Anyone know if there is a clutch/parking/charging correlation? I found this a bit surprising actually. After reading the AECS article above, it seems timing (as a car-wide electrical term) is pretty critical. I'm wondering if adjusting the park mechanism might stop this banging...

 

Well, nuts. Yes, actually peanuts. A squirrel apparently stashed his goodies under the air box, and in the process nibbled on the #1 injector wiring, right at the connector head. When I pulled on it, it basically fell off. PO301 was legit, as I'm sure the wiring wasn't making contact with the connector consistently, if at all. I'd backprobed the harness earlier but not actually at each connector.

Bought a new FI connector and soldered it in, problem fixed. Pulled my spark tester out after the fact, and verified all of the coil packs are good. Including the brand new one (I didn't need). A little lesson in humility, and attentiveness. Had I pulled the airbox early on, I might have discovered the peanut shells much earlier.

All the symptoms I described now fit nicely into the PO301 misfire category, even though they were intermittent.