SOLVED/REPAIRED - Misfire Mayhem - P0301, P0302, P0300

Yea that's the problem in the realm of scan tools nowadays, there are so many different choices at all price point's but you really have to do alot of research to figure out what does what and what is the best value for what it does.

There are alot of really quite basic scan tools that IMO are priced way to high for the limited features they have. Then there are others that have a ton of features at a relatively low price.

The Launch I bought last year can do 90-99% of what the OE tools can do on most any vehicle made since 96, it's under $1000 when it's on sale.

 

The ones I ran into had anywhere from 115K all the way up to 230K so to hear it happening under 100K is not totally outside the realm of failure given their overall life expectancy seems to be a mixed bag. Sort of like the old GM 4L60E transmissions.

Granted I haven't read through this entire thread because I haven't had time but I did see some mentions about oil inside the tubes. If it's a lot and it's getting into the plugs then he should definitely start there because oil excels at preventing conduction of electricity, in this case, spark.

 

Okay. I read through your post where you talk about swapping coils.. did you chose where to put coils based on cylinder number or based on where you remembered the coils being from? it's a find the ball under the cups game.. with my point being that the coils didn't end up in their original placement. and I wonder if there was a mistake, and coil 1 ended up on cylinder 2. It's a reach, but maybe try swapping the coil from cylinder 2 to somewhere else.

edit: another thing that highlights coils for me is, well, when you jam the throttle, they amplify current or whatever. And generate electrical interference proportionately. fuckin. if they're no longer so well insulated, you'd have a fault that appears under heavy load. and its something that got moved around before cyl 2 had issues..

 

Saw your earlier post, too, and the only thing I have to contribute is that not all Toyota 2.7L are the same. The 95-2004 Tacoma 2.7L 3RZ-FE was notorious for burning valves as the mechanical shim+bucket valve train needed adjusting at 90k and nobody ever did that (including my buddy. He had a 99 Tacoma and I replaced the head for him at 130k due to 3 burnt exhaust valves causing misfires. Leak down revealed the issue.) Those motors were also notorious for cracked exhaust manifolds that contributed to burning valves but that's not relevant here.

What is relevant is Toyota upgraded to hydraulic lifters in the 2005+ 2.7L 2TR-FE (the motor in this post). That said, the lifters can and do go out on these motors (especially if oil capacity and grade history is in question. I've read the lifters are either good or bad; there's no adjusting or in between) and that could be a contributing factor to the problems OP is having. Just curious why the problem is now migrating so I'll be following the solution. Either way, if it were me, I wouldn't mess with another compression test but I would take that time to do a leak down test.

Good luck, OP!

 

A compression and leakage test is always a good idea here. The leakage test in the right hands will also tell you if there is pressure leaking into the intake manifold which is usually a sign of bad valves. When other tests failed and there was still a question mark about the overall engines mechanical we would bust out the cylinder leakage tester even if it was not having head gasket issues.

The compression test should be done two ways. Statically with the engine off and dynamically with the engine running. The engine running test is a pain in the ass (which requires you remove spark plugs individually and keep the rest hooked up, shraeder out of the comp tester, start the car and check) but it does reveal a lot of information. Possible running pressure could vary a ton amongst different Mfg engines but at the end of the day what you want to establish is whether or not there is a variance in running psi amongst each cylinder. They should all be the same. If there is even a variance of 5 psi across any of the cylinders then you definitely got a mechanical issue.

 

Post some pics of these suspect coils. Can you see carbon tracking (arcing) on the coil boots? Or on the porcelain of the old plugs?

When I play move-a-coil I mark them with grease pencil or permanent marker so I don't lose track of the suspected bad one

Also, like I mentioned earlier, a simple vacuum gauge can reveal a valve issue in the cylinder head. The needle will fluctuate rapidly from the changes in manifold vacuum

 

Neither of your examples. When I say 1 to 4, I mean exactly "AT THAT MOMENT, whatever was in cyl 1 to cyl 4, and whatever was in cyl 4 to cyl 1", so just follow my write-up. I had written my plan out a piece of cardboard in the garage that I wish I kept right now.

Honestly, it shouldn't matter only because of one very basic but important point I mentioned in the OP: after the very first CEL that was cylinder 1 misfire only, coil pack #4 was moved to cyl 1, and vice versa, AND spark plug #3 was moved into cyl 1 and vice versa.
SO: cylinder 1 had the #3 spark plug AND the #4 coil pack AND THE VERY NEXT CEL was still only cyl 1 misfire and both cyl 3 and cyl 4 had no news to report.

Whatever you might think was screwed up in the troubleshooting, it still doesn't account for the original cyl 1 misfire problem remaining.
Hence, I'm leaning towards a mechanical problem but would like to know with above 70% certainty before I go joy-ratcheting around in the engine.

 

Unfortunately, At this point. I too am leaning towards a mechanical issue.
Sorry man. Hopefully you get luck before you have to take a deep dive.

 

I really appreciate it man... I'll take all the luck I can get from wherever I can get...

 

I will this week while I'm running the tests. Also have a coil air-gap tester on the way

 

Going to try this week. Will report back with pictures and results.

EDIT: nice truck btw

 

Thank you. I really liked it more a few years back but it's seen some mileage under the hot sun and the paint has been weathered pretty bad on the roof. Could definitely use a SOLID detail that much is for sure!

 

No offense meant. I've just got a lot of experience screwin stuff up thanks to my special brain.

 

In the process of doing leak down tests.

Before we talk results, can anyone confirm what my shop manual says about finding cylinder TDCs is correct?

 

I still think you are all getting head faked with the misfire codes and questionable comp results. If the comp sucked across all four cylinders, the engine would run poorly all the time with low power. Instead op tells us the truck runs great (that is our que that this is a situational, not a global problem) EXCEPT

if the situation getss bad enough to kill the engine, it is no surprise that a few misfires are recorded along the path to that failure. Not really relevent which cylinder had the code. If it was bad enough to kill the engine , it is a global problem. A bad plug or coil is not going to kill the engine. Need to be looking more globally than one cylinder.

it’s obviousl the op doesn’t like my ideas and that is fine. But you guys need to focus more on the symptoms described and less on the obd codes. The pros here will tell you that you cannot fix problems just by looking at obd codes. The are all great clues, but need to be leveraged in a diagnostic strategy and not chased down individually as if they are definitive indicator’s. Let the symptoms be the guide. There are no reported misfires. The report is if i step on the gas going uphill, the engine dies.

 

When I said the “the issue pops up when accelerating uphill”, that’s when the CEL registers. To be honest, I would bet a year’s salary that even without the CEL on, if I connected the OBD tool on the very first ignition after clearing codes, there would be a PENDING MIL code that the ECU hasn’t confirmed yet, so no CEL.

Other than that, the car does feel sluggish (post #20).

Waiting on TDC procedure confirmation before I share leak down tests results.

 

Looks correct to me. Step 6 is the important one. The gauge needle will jump up a bit when the compression stroke starts, then just bring the crank pulley up to TDC. Go to each cylinder in the firing order and repeat

Have you done a second compression test? Same numbers?

 

Leak down test results (all spark plugs removed and working with 1-3-4-2 firing order):

Cylinder 4 TDC (using as my test control cylinder):
Tested fine, about 8% of PSI lost

Cylinder 2 TDC:
Massive pressure loss of about 80% of PSI. You can hear and feel air coming out of the cyl 1 plug well.

Cylinder 1 TDC:
Same loss of about 80% of PSI except air coming out of cyl 2 plug well.

Cylinder 3 TDC:
Loss of about 30% of PSI, some air coming out of cyl 2 plug well but nowhere near as much as between cyl 1 & 2.


My diagnosis is the head gasket is blown exactly between cylinders 1 and 2, and partially between cyl 2 & 3.
Given there is no smoke out of the tail pipe (no burning oil), is it safe to say the engine block is okay?
Also, not sure if the HG seal is broken with one of the engine coolant bays in the block (no white smoke from tail pipe), but does it really matter knowing the HG needs to be replaced?

 

Well based on your test it seems you now have cause to tear into it, no way to tell for sure what's wrong until you tear it down and inspect it but it does sound like the HG is blown between cyl 1 and 2.

If it's not consuming oil (your not having to add oil between oil changes) odds are good that the bottom end is fine.

 

Not sure if I should ask here, but if I'm going to have a shop do the head gasket replacement, what else other than the water pump and thermostat should I be considering having changed out?

Engine has 93k miles, but I'm thinking long-term