Having a misfire but can't locate anyone with same problem

Hello everyone, I'm new here. I've had my tundra since 04. Never a problem. But recently I came to a stop and it started idling rough. No codes. I changed the fuel filter and cleaned the maf sensor started it up and still the same but this time I got codes 300, 301, 303, 305, and 307. I replaced the sparkplugs, Still same. I swapped all drivers side coils to the pass and still the same codes. Checked all the vacuum hoses and good cleaned my air k&m filter and throttle body. Still same. Even took my 02 sensor off to see if maybe the catalytic converter was going bad still nothing. Only thing I have done is clean the injectors or change the fuel pump. Any ideal would be greatly appreciated.

 

perhaps a vacuum leak? Brake booster vacuum line and PCV valve are both driver side.

 

I'll double check them thanks

 

Is ther a particular brand to use for the pvc valve, like denso or can I use any brand for that

 

might want to check for a head gasket leak. They sell cheap kits for that.

Or maybe timing is off by a tooth on that side? Got to think of things that would affect a whole bank, rather than a single cylinder.

 

It's funny of all the people here who had a similar issue, none have posted the cause. Only one guy but he was rebuilding his engine.

If it was random misfires, and you've been driving for a while before encountering it, I'd highly suspect a worn out fuel pump (like me).

 

That's what I'm thinking. I got 206000 miles on original pump. Is time to change?

 

OK update. I ended up replacing the pcv valve. Just bought one at autozone to see if helped. Installed and cleared codes ran for awhile revving the engine and no codes. To it for a drive today and I get 300 301 303 and 305, but no 307 now . I did disconnect the battery for a day. Should I just drive it get the computer to reset it's self?

 

Hard to say when it’s only one bank of the engine having issues. You can certainly check the fuel pressure when it’s normal and when it’s acting up. You’ll need a gauge and a banjo to schrader adapter to connect it the fuel rail.

Ruling out moisture would be easy by putting in dry gas and filling the tank.

 

What my code reader shows.i know I need a up to date. The low reading are at idle and the higher ones are at 2500 rpms

 

More pics

 

I had just filled up and was on the way home when it started. I buy the same, costco. I did add a can of seafoam when it started

 

And I never let it go below half a tank

 

It's odd that you have a high positive long term fuel trim on one bank and a high -ve on the other. That high a -ve means the system thinks you're running rich and is dialing back the fuel delivery. But the other is the opposite.

 

Could it be from the clogged pcv valve on the driver side valve cover

 

I took those readings before I replaced it

 

O2 sensors help the computer calculate fuel trims

 

It's possible I think. Best thing is to take new readings. We're just guessing otherwise.

 

What I'm getting now ones at 2000 rpm the others at idle. No check engine light. It did come on then went off

 

I'd give it some time for everything to complete the 're-learning' process.

 

Well I took it for a drive 15 minutes in i get the blinking random misfire light. All 4 driver side misfire codes..
Cleared kept driving and the blinking random misfire light would come on then turn off. Drive more come on again and stay on after flashing same thing random misfire 301 303 305 307

 

That makes me think (and I am not an expert at all) that it is less likely to be the fuel pump. Because both sides would be affected. I know I mentioned a head gasket, but it's not really common for all 4 cylinders to be affected at all of a sudden, all at once by that. I really would check the timing. If it's off by just a tooth (for example caused by a weak tensioner), maybe that would cause it to misfire? Does you scan tool have a misfire counter?

 

When you cleaned your injectors did you get all the old o-rings out? Make sure the injectors were seated?

did you take the manifold off at any point?

This happen to me once when a nut fell into my value opening and got stuck

 

I haven't cleaned the injectors yet. Thinking thats gonna be next. Manifold has never been off

 

I had the timing belt redone at toyota like 30 thousand miles ago. If it was a cam or crank sensor would it give out a code?
What do you mean by misfire count? Like how many times it misfire revaluation?

 

If it's all 4 cylinders on one side, would it be the cam position sensor? You've covered everything else.

 

That's where I'm leaning. But I'm not a mechanic and I would have expected a P034x code. The reason for the misfire count was to see if it affected all cylinders on that side equally. It's going to be something that affects a whole bank. Fuel rail seems unlikely as it's doing a negative fuel trim on that bank, so it believes it's getting too much fuel and is dialing it back (or not enough air?). I'd want to check to make sure the spark is consistent and regular. If it isn't, could even be the signal to fire that bank of coils is bad. I read somewhere that the ECU has two drivers, one for each bank. No idea how accurate that is. I mean, the internet, right?

Actually, yeah, look for corrosion around the ECU from a water leak into the cabin.

 

And I still think you should check the timing. I wouldn't trust a dealership to tighten a gas cap these days.

 

Alright I'll check. Thanks

 

Symptoms:

Only bank 1 impacted.

ECU thinks it’s running rich.

ECU gets that info by reading fuel/air ratio after combustion via upstream sensor.

…

My #1 suspect is your upstream A/F (O2) sensor is sending bogus info to the ECU, and causing it to trim fuel, thus resulting in bad fuel/ox on that entire bank, and the bad fuel/air ratio is causing misfire.

And it should likely run normal for the first little bit of startup, and if you clear the ECU, by removing the negative batt cable for 10min, it will run until relearn completes.

If you’ve never replaced your O2 sensors since purchase, that would convince me fully it’s the issue. I’d swap all four now with authentic Denso units, and be done with it for another 15-20 years.

Replace the driver side upstream sensor.

www.densoautoparts.com to look up your part number.

DO NOT buy it on scAmazon or fleaBay or any other counterfeit-riddled website. Rock Auto and Summit Racing will have your best pricing.

Stick with Denso brand, or a locally sourced Bosch unit.

Be sure to pull the negative batt cable before you start the install, then reattach after, so the ECU enters relearn mode after.