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2008 Toyota Tacoma 4×4 2.7L 4 Cylinder Manual Trans. 69,000 Miles. I am new to this forum although I have watched many, many ETCG videos on youtube and figured this would be a great place to check. In a perfect world ETCG would be my neighbor. If only things could be so simple.
I’m just going to copy and paste the post I put up in a Tacoma forum.
SO…
Today me and my Uncle took off my plenum. It was filthy and needed to be cleaned (the reasons for that can be found here Filthy Air Intake System.
We got that all off. Stuck it in his parts washer and cleaned it out as best as we could. Blasted some air from a compressor down into it to make sure it was free of loose debris. We stuck that bastard back on and put everything else back together. I fired up the truck and it ran normally. I drove it on the freeway for about 30 minutes. No problems.
I go to the car wash and to give it a bath. I was spraying junks of mud off of parts of the skid plates and frame.
I go to start it up and the starter souded, funny and it didn’t idle very well. Let it sit for a while then tried to start it again and it really struggled getting started. There was a decent amount of additional vibration (at idle).
I get back on the freeway to go home and it runs fine on the freeway. Solid 45 minutes of driving. There has been no indication this entire time as to a loss of power or performance.
My check engine light has been perpetually on (this whole time) because of my stupid Evap Emission control system. I’ve had this checked twice and it’s this stupid system that has a tiny leak that has ZERO effect on how it runs/drives/idles. Now I figure I might as well get a scanner hooked up to make sure there aren’t any additional codes considering how strange it’s behaving. This is what I find from AutoZone.
P0012
-Camshaft position “A”- timin over advanced bank 1
1. Blocked oil passage
2. Mechanical Timing fault
3. Failed OCV
4. VVT controller assembly faultP0301
-Cylinder 1 misfire detected
1. Weak/Missing spark
2. Plugged fuel injector
3. Engine mechanical fault
4. Large vacuum leak specific to cylinderP0031
-Oxygen sensor heater control circuit low- bank1 sensor 1
1. Open or short circuit condition
2. Poor electrical connection
3. Failed Oxygen sensor
4. EFI relay faultAnd yes, I double checked to make sure that all hoses and connectors were back where they started out today before we took the plenum off. Like I said earlier, there is zero loss of power and the truck drives exactly like it did before any of this started (aside from taking much longer than normal to start).
I talked to the manager, Pedro, who really sounded like he new his stuff. I was very inclined to take the advice he gave (of all the guys I’ve talked to at this particular AutoZone this was one of the few guys who really sounded confident and very educated about automotive stuff). He believes the number one culprit is the camshaft sensor. His second guess would be oxygen sensor on the exhaust before the catalytic converter.
He said the cam sensor would cause it to struggle to start and could throw all three of those codes. The reason he puts the oxygen sensor at number 2 is that I could have sprayed it really good while washing the underside of my truck.
The thing that makes this all very, very confusing was that while we were sitting there talking about all this stuff, my truck’s idle smoothed out. Pedro put his hand on top of the valve cover and commented about how smoothly is was running now.
I just now went out to start it and it’s still taking longer than normal to start. I’ve called a few repair shops already about getting the sensor diagnosed and I was told about $140 just to diagnose the problem. If I could get some insight on how to diagnose the sensor myself I would really appreciate it. 140 just to be told, “It’s good” or “it’s bad” is not ok with me.
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You would need a lab scope to see if the sensor is good or bad by monitoring the wave forums in correlation with other sensors on the vehicle. That’s what you pay for with diagnosis as most DIY’er do not have the equipment needed to successfully diagnose these types of codes.
You would also need to be checking the integrity of the cam sensor circuit too.
Given the codes I was given and considering I have no loss of power or performance wouldn’t it be safe to assume its one of those two sensors (oxygen and cam)? It has always fired right up when its cold and taken longer to start once its warmed up. But since yesterday its seems to have gotten much worse.
And you can’t use a multimeter to check and see if these sensors are operating correctly?
hello, please don’t throw sensor at it! Have you checked your battery’s state of charge and had it load tested? Have you checked the terminals and cables for corrosion (for the cables it could be inside the cable not visible) I have seen batteries with low charges cause the car to throw all kinds of wired codes. Just check the simple stuff first with hard starting. It didn’t seem to me you had the problem before anyway. So make sure that’s all good then go deeper.
My wallet isn’t deep enough to throw parts at anything. I had my battery checked a few weeks ago and it was fine. It’s not turning over slow, it’s just taking longer to finally start up. I could stop by les shwab on my way to work and have them check it out just to be sure.
I would address the o2 sensor first.check the fuse for
the heater circuit.also check the connector and wiring.
see if water or mud is in the connector.with the scanner hooked
up.read live data.the o2 should be switching rapidly.as for the
cam sensor.pull the connector and check for water or damage. Btw
when the intake was removed and cleaned.were new gaskets used?
the cylinder misfire. go to that plug and pull it. see if fouled.As for the o2 sensor heater code, if you have a DMM you can measure the resistance of the heater coil of the sensor. A service manual will tell you what resistance it should be but it def shouldn’t be electrically open.
[quote=”FRYBOTH” post=31751]My wallet isn’t deep enough to throw parts at anything. I had my battery checked a few weeks ago and it was fine. It’s not turning over slow, it’s just taking longer to finally start up. I could stop by les shwab on my way to work and have them check it out just to be sure.[/quote]
Yea i would check the battery but lets say its fine and the terminals are good i would address the misfire code first because In my opinion the 02 code is set DUE to the misfire. Check the usual as to a misfire and continue diagnosing as needed. You may end up finding the cam sensor is the cause of the misfire just i don’t think those things go often (correct me if Im wrong) So if you do determine that be sure you have some evidence for it. You may find a service manual helpful. (also you could try resetting the codes and seeing what happens if they re appear and/or how fast?
I picked up a Chilton manual today. I haven’t found anything about resistances for certain sensors, Mayne I just haven’t found it yet.
But, after reading the replies and reading the section in the manual about how to remove the intake manifold I have to admit I didn’t use a new manifold gasket when we put it back on. The old one looked fine. Could this be the cause of the misfire code? One of the probable causes read, “large vacuum leak specific to cylinder”. Could the old gasket not be seated properly? The only reason this confuses me is that I’m still not experiancing any of the symptoms of a misfire. I still have just as much power as I had before. Could the misfire have been a onetime thing, that then tripped the oxygen sensor code?
Or maybe its a combination of poorly seated gasket, bad o2 sensor and a bad cam sensor?! Ugh, I am so very confused. But all the comments have been very helpful, please keep it coming!
By the way the battery checked out fine.
reusing the old intake gasket is probably the culprit. spray around the intake with carb or t/body cleaner and see if the idle changes. you can hook up a vacuum guage and see what it reads at idle and under load.
[quote=”FRYBOTH” post=31697]Given the codes I was given and considering I have no loss of power or performance wouldn’t it be safe to assume its one of those two sensors (oxygen and cam)? It has always fired right up when its cold and taken longer to start once its warmed up. But since yesterday its seems to have gotten much worse.
And you can’t use a multimeter to check and see if these sensors are operating correctly?[/quote]
Those sensors are changing so rapidly a multimeter would never be able to show you that. You need a scope because a waveform is what you would be looking for.
Have you checked the fuel pressure before the key is turned on? How does it compare to spec? Does the fuel pressure hold or does it drop substantially over time? Your back flow preventer may not hold the pressure in the line so when you go to start it it may be slower to start because the line doesn’t have enough gas in it.
I can’t say I’ve checked for fuel pressure. I don’t actually know how to be honest. But how does that explain how easily it starts in the morning after sitting overnight?
So is there a general consensus I should yank that intake manifold off and put a new gasket on there? Again its confusing to me because if the gasket was bad or not properly seated I feel like there would be more of a dramatic effect on the driveability.
[quote=”FRYBOTH” post=31780]I can’t say I’ve checked for fuel pressure. I don’t actually know how to be honest. But how does that explain how easily it starts in the morning after sitting overnight?
So is there a general consensus I should yank that intake manifold off and put a new gasket on there? Again its confusing to me because if the gasket was bad or not properly seated I feel like there would be more of a dramatic effect on the driveability.[/quote]
I would agree that the gasket may not have sealed right if it was reused and I can see how moderate misfire may not effect engine power (the computer will try to compensate for any mix up in the air/fuel ratio)
For the heck of it try the carb spray around it and listen for idle changes.
this gasket for me would be my prime suspect as this point.[quote=”IRONMAN0992″ post=31784]
I would agree that the gasket may not have sealed right if it was reused and I can see how moderate misfire may not effect engine power (the computer will try to compensate for any mix up in the air/fuel ratio)
For the heck of it try the carb spray around it and listen for idle changes.
this gasket for me would be my prime suspect as this point.[/quote]Well I sprayed TB cleaner all over that bastard when I got home from work tonight and got nothing. Just sat there at idle, no noticeable change. :huh:
I mean, we put the manifold back on and I started the truck up just like I always do. It took a few cranks before it finally fired up (which like I said before has been the norm). The big change seems to come from when I washed my truck. I had to shut off and turn my truck back on twice before I got the car wash and it was doing it’s normal thing. It was after the car wash that all this seemed to start. Ever since then the amount of cranks it takes to start up has about doubled. It still starts much quicker in the morning when it’s cold and has been sitting, but even today it seemed to burble a bit, usually when it’s cold like that is the only time I feel it starts like it’s supposed to, after one or two cranks.
I mean I might as well replace that gasket just for peace of mind, and since I should have already anyways. Then I’ll take the time to check out the plug in cylinder 1.
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