P0300 check engine light no power

Hi all,

I am hoping we can figure out and find this returning problem together.I own the tundra 2010 5,7L V8 SR5 2WD AT for over a year now.In the beginning the check engine light was flashing no power and you could feel I had more then one misfire, I checked the error codes with a universal obd reader and it came up with only p0300,so I decided to replace the spark plugs.

After a month the same code came back,meanwhile I had techstream and this brought me deeper into the Ecu and showed me the specific cilinder wich was causing the code,so I replaced the 2 coil packs of the cilinder that where causing the codes.

Now the strange part of the story:
Car runs great,on Petrol and LPG,is does not Mather on wich fuel it runs to pop up the check engine light and trowing the p0300 code.But the problems always come back after like 1,5 month.Meanwhile i had the problem like 4 times,if you stop the car turn of the engine and start it back up it runs great again.

For now I already replaced the coil packs of cilinder 1,2,3,4,5,7
Because they showed up in the monitor misfire counts techstream.

Today the same happend, I was driving on the highway 100km/h,2000rpm,engine/car started shaking,no power,rpm went to 4000 because of engine malfunction,drove home,felt like driving a tank (shaking as hell) hooked up the techstream and the monitor was showing cilinder up going misfire counts on cilinder 2&4.These already have been replaced.(see pictures attached)

Downside in finding the cause is when you turn of the engine and restart it will run great for 1,5month.

Does Anyone have any suggestions ?

 

Wiring damage? Or fouled out spark plugs??

 

today it happend again, just 200km later,no power misfiring on cilinder 2&4
I will start swapping the coils from cilinder 2&4 with 6&8, as soon as I turned off the ignition/engine and restart the engine runs perfect again..

 

Check the cam and crank sensor wires for burning or damage, loose, corroded connector etc.

 

I will check them but if this would be the case the should come up in the DTC codes I would say

 

Sometimes it will take a complete failure to show up. On intermittent items it may not show as it has not completely failed.

 

checked cam/crank sensor wiring connectors,looks al good.Took out the sensors to see if they where dirty or damaged,too bad... they looked good.
Switched coils from 2&4 to 6&8.Only time will tell...

 

Switching coils around would have been the thing to do before you went whole hog and replaced them. Did you put OE parts back in for what you took out? You can create extra problems by just throwing parts at a problem without fully diagnosing things first.

How does the live data look for the cam and crank sensors?

 

In the past times the error occurred I switched the coils and ended up replacing the faulty ones, by Toyota denso original ones.But this time the error comes back 2 times till now on cilinder 2&4 that’s why on the second time I swapped the already replaced coils from cilinder 2&4 to 6&8.
I did not find the data from cam and crankshaft sensor yet in techstream,I might have a slightly crippled version
Downside in finding the problem is ,before it happens again you could already have emptied 3 fuel tanks.I wish the problem was always present ...

 

With all your misfires, I would use BG Products 44K fuel system cleaner. It is not cheap stuff @$30 dollars per can, but this is the best in the market that I can find that works well. I have been using this stuff for years and it has proven itself with misfire. In one tank full it will clean up those injectors. Your injectors may be causing the random misfire. It is worth a shot. Also, have you removed the negative battery cable to clear the memory and start over? I would also do that along with the 44K. I would also stop using the LPG and stick with fuel until you get it sorted out. The LPG may be giving you additional problems that linger long past its use.

 

Little update, cleaned the throttle valve,replaced 2 vacuum lines while I was at it.Checked connectors/wiring of crank/cam sensors.Filled up the petrol tank and added fuel injector cleaner to it.

 

lets hope you get some good results.

 

2 Fuel tanks emptied no problems but
today the p0300 misfire multiple cilinders occurred again after 20km drive to work, hooked up techstream cilinder 2 & 4 showing misfires again,after turning ignition off/on car runs smooth again,any ideas/suggestions ?

 

Was just wondering what type of injector cleaner did you use? Are you using the same petrol station for every fill up? Sounds like it (injector cleaner) may have been working and maybe the petrol station may have contaminated petrol. I would at least try another full tank with cleaner in it. You may have had a seriously dirty injector system.
Also what brand of spark plugs are in your rig right now?

 

When the problem first occured i replaced the spark plugs for original Denso's.
I used a few brands injectorcleaners, Wynns, Mannol and Makra.I always fill it up at same petrol station Euro98 (E5)

 

Good on the spark plugs. Toyotas are very sensitive on plugs. Denso or NGK are the only ones that work well with the Toyotas. Also with the plugs, your owners manual states the exact number for the Denso and the NGK. No cross reference brand and or number, the exact number only. I know some auto parts stores will try to sell you cross reference because they don't have the exact number, don't do it, say thank you very much and go find them somewhere else. If you don't know this, this has been an issue with plug replacement for a long time on Toyotas. I am only throwing this out there because a lot of people don't know and put a different plug number/brand and still have missing after the job is complete.

Sorry the BG products 44K is far superior to the brands you listed. With this type of problem I would not waste any time with anything but 44K. I am not a rep for the company I just know this products works through experience.

 

Update :

after replacing the hoses/tubes of the LPG system no more error codes, engine lights or lack of power.Running like it should for over 2k now

 

What was wrong with #2 and #4 hose? Picture of bad hoses?

 

it seemed like the hoses had a restriction wich where not visible, but a LPG specialist informed me about this.

 

Seems like the Flex Fuel rigs come up with strange issues. This is not the first time I have read problems with missing on a flex fuel rig. Not always the same problem though.