What is going on?

Started my truck sounded a little loud and idle is rough. Put OBD reader and got codes P0351, P0354, P0356 and P0357. I swapped coil packs around and still same codes. Changed plugs, old ones looked good. I appreciate all the help I can get.

 

Coil packs are the original, OEM coil packs?

If I recall correctly on the P035x codes, the last digit is the cylinder of misfire, it was a smart thing to test swapping the coils around between those not misfiring and those that are.

No signs of wiring issues on cylinders 1, 4, 6, or 7? No signs of anything being chewed there? Tagging the cylinders these codes would cover.

 

Was truck running fine before hand ?
Any work done lately ?
Did you reset codes after swap ?
Coils 1, 4, 6, 7 going bad out of the blue definitely odd !

 

Truck was running great. Started feeling a low rpm miss it was rainy didn’t think about it. Next day I started it up and this is what happened.

 

No work done. I did reset codes. I have replaced plugs and new battery since it started.

 

If no service done to the truck at all during the last 18-24 months (prior to it happening)...

We're coming out from the back side of winter, and you're potentially in mice country, my initial thought is rodents chewing on wires with how random that cylinder pattern is.

 

Curious, did you check for any signs of rodents nests, any impact to the engine harness or its loom, any damage at or near the bulkhead, and you check the state of the engine bay fuse/relay box for corrosion?

 

I did try to look at wiring but didn’t see anything. I also sprayed starting fluid around vacuum lines just hoping.

 

Its not random. Thats every other (from the firing order).

 

Looked in fuse box in engine bay no nest just dusty.

 

Yes doesn’t seem random on firing order.

 

The cylinder numbers seemed odd and this might not help but looking at the codes in FSM and the below info leads me to believe you have an ECM problem or harness problem somewhere due to IGF1 return signal to ECM from Cylinder 1, 4. 6, 7.
While it seems odd but IGF1 is for cylinders 1,4 6,7 and IGF2 is for 2,3,5,8

 

Were those 4 plugs any different than the other 4? No other codes?

 

Right, I mean it seems random from the perspective of being both non-linear + non-singular.

Like, if it were a single failure, I'd think bad coil. If it were the 2-3 foward-most cylinders, or all cylinders on one side, I'd think it was an end-of-harness thing. But the misfires on the cylidners it's happening on, the chances of nicking the group of wires that would misfire seem unlikely w/o pulling up the EWD. The fact the idle is rough suggests to me something is actually misfiring, but it's curious what/where that would be.

Edit: Bubba pulled the EWD. I guess that makes it pretty clear. I'm still thinking rodents, maybe up under the glovebox area where the ECM is? (pretty sure it's under the glovebox). Maybe a water leak into the ECU area via the dash via the infamous cowl leak in the dedicated leak thread? That would also jibe with @Grumpy61 's note about this starting in the rain...

 

Are we thinking looking around the ecm for wire damage. L-B is lavender and black. Coming of pin 24 of ecm.

 

Toyota's idea of "lavender" is basically blue, in my experience. And I'm not colorblind/color-deficient.

If I were to next-step on it, based on what Bubba posted, I'd try to get a visual on the ECM, detach the harness, look for harness corrosion or damage, confirm pin 24 of the ECM is blue/black stripe or purplish/black stripe, make sure it's clearly not damaged, and look for any signs of corrosion (green marks) on/around the ECM itself.

I'm pretty sure its' going to be taped up starting about an inch out of the ECM, so tracing wouldn't be easy. But you could potentially test for continuity from the injector bank harness end to the 24 pin of the ECM connector, I suppose.

 

I'd add in case you've never seen before. Leaks into the interior of the vehicle, either from the cowl or the windshield glass, typically result in stuff like this:

https://www.tundras.com/threads/02-tundra-electrical-problems.45605/#post-1174202

The fact you mentioned driving in the rain when this started, it just ... I dunno, still think it's possibly related.

 

These trucks can be a bit finicky with voltage and ground issues. I would check battery, grounds and power cables for corrosion as well.

 

Ok I will go look at ecm and check for corrosion and rodent damage. I m not familiar with the cowl leak but passenger floor is damp. I will let you all know what I find on ecm. Thank you all.

 

@Grumpy61 check out this thread: https://www.tundras.com/threads/definitive-2000-2006-cab-area-rain-water-leak-thread.70464/

Specifically, pay attention to the video at the bottom of the 1st post.

Almost all of our trucks have that specific leak from the cowl, but it drips into the HVAC system and overflows through the blower, which should be below your ECM, if I recall. That's not to say your windshield isn't leaking water when it rains also, but ... whatever.

However, if the passenger floorboard is wet, solid chance you've got that issue, and water in the cabin can have all kinds of potential effects not limited to mold/mildew which, once rooted, is impossible to get rid of.

 

Going down a road I have never been but as @shifty` said, continuity check from ECM to injectors. If I'm correct on harness route, it reaches cyl 6 first. On ECM it's pin 24 of connector E 7 if choose that route. Pin 2 of any of the cylinder connectors is IFG 1 signal from ECM.

 

One last thing before Golf !

 

Just caught this, our Tundra color codes have L as Blue or unless you are calling lavender blue ?

 

Ok. I checked ecm to coil good continuity. Pin 2 to gnd reading open. Anything else I can check.

 

Even tho you feel good on continuity and if you have a volt/Ohm meter, suppose you could check for the 5vdc.
With my IGN on/ENG off on my 04, there is 5 vdc @ pin 2 to batt gnd. If not, I would then check for 5vdc output of ECM at pin 24 of connector E 7.

 

I will give it a try. Thanks

 

Just re-read something @KNABORES said and maybe others….also what you said.

I’m re-posting the chart from above where it shows you should have a short not an open(OL) when ECM E 7 connector is unplugged when checking pin 2 of a coil. Suggest following the procedure of unplugging coils and E 7…. re-check pin 2 of coils. We have storms and lost power, difficult to add more info. Check gnd strap at firewall about cylinder location, all gnds as @KNABORES mentioned.

 

I'd say at the bare minimum if there is a possibility this is from water intrusion then go ahead and replace at least the 1 or 2 (can't remember) cowl clips that leak into the floor and give whatever may have gotten wet some time to dry and see if anything changes. Might save you from throwing any parts at it anyway.

 

Ok I checked pin 2 and got 0 volts went to pin 24 on j7 got 0volts. Any more info you can share?

 

Just to make sure, when checking at the coil plug pin 2, the E7 plug was plugged into the ECU and you had IGN on/EG off ?

Also I am not understanding “pin 24 on j7”

The pin 24/E 7 check is to assure the ECU is out putting the 5 vdc that goes to coil with IGN on/ EG off. Perhaps you are saying that and I am simply misunderstanding. Bottom line, if there is no 5 vdc out of the ECU pin 24, that’s not good.

Simply to make sure you are checking things properly, consider checking for 5vdc @ pin 2 of one of the good coils 2,3,5,8 with ECU plugged in and IGN on/EG off. You can also verify you are checking the output properly at the ECU by looking at E 7 pin 25, which is the 5vdc output to the good coils 2.3.5.8.