P0306 Code Problems Diagnosing..

[tylambert]

2000 4runner sr5 3.4 v6
About 5 or 6 weeks ago i began to feel a lack of power or a kind of shaking i guess you could say when i was on the interstate and getting up to speed and when i got on it to pass someone. At first the CEL only blinked but after a few days it stayed on.. i got the code read and it came up a cylinder 6 misfire. I am currently going to school to be a mechanic and i am still new to all of this so i am hoping its something simple and cheap because i do not have much money. Within the past year i have changed the following: Spark Plugs and wires, Fuel pump, 2 of the 3 coil packs and ran fuel cleaner through a tank of gas. I have already switched the spark plugs and wires to test them.. Also i took it to a Toyota dealership just to get a diagnosis and the told me that it was caused by a loose spark plug and spark plug wire.. may have been possible but very unlikely because it did not fix my problems and they even test drove it and said the CEL didnt come back on. but i have only had it come on while on the interstate at higher speeds and it came back on a day after. I feel it was just a way for them to say go home.. so that was $50 wasted. It is frustrating and annoying and i would just like to fix or at least know my problem! most of the people on here seem very smart so any help would be appreciated! Feel free to ask any questions also!
Thanks,
Tyler

 

[HiluxHunter]

I know this may sound overly simple but they are not mentioned in your post of things you have changed/checked.

Try air filter and fuel filter. These become more critical under higher power demands, but might not show up under normal operations until there is more of a blockage. The higher demand for power the more fuel and air required to keep things running smoothly.

Also there is a ton of things you can learn about how your engine is running by spark plug analysis. Even if the spark plug is "good" it might be worth analyzing them for further diagnoses.

A quick google search brings up a lot if info...

NGK Spark Plugs Australia

Best of luck.

 

[tylambert]

I know this may sound overly simple but they are not mentioned in your post of things you have changed/checked.

Try air filter and fuel filter. These become more critical under higher power demands, but might not show up under normal operations until there is more of a blockage. The higher demand for power the more fuel and air required to keep things running smoothly.

Also there is a ton of things you can learn about how your engine is running by spark plug analysis. Even if the spark plug is "good" it might be worth analyzing them for further diagnoses.

A quick google search brings up a lot if info...

NGK Spark Plugs Australia

Best of luck.

Thanks for the quick help!
My air filter does need replacing but its not too bad.. would that cause the code though? and i forgot to add in there but in the past year i have replaced the fuel filter!
thanks again!

 

[tylambert]

also i get what your saying about the spark plugs and i have pulled almost all of them within the past couple weeks.. i see nothing out of the ordinary but that was the first thing i did was look at them!

 

[tylambert]

BUMP! i need help!

 

[Drcoffee]

misfire

 

[runnyrunnerton]

Ive battled with PITA ass codes a bunch. WHat Ive found is basics, basics, basics.

1. Your O2 sensors need to be working. Front and Back. Check them with a resistance meter.
2. Post what steps youve taken from advice already given. Cleaned the intake, airfilter, airfilter, changed fuel filter. etc.
3. If you have run fuel cleaner thats good, i have gotten bad gas before. try a little ethanol free gas if you have it in your area from a reputable station (brand name like shell, not bobs drywall, groceries and gas)

I have always had terrible luck with o2 sensors, regardless of the codes, when i get a check engine light, if it is even close to related, i check it. I once spent almost a grand with a mechanic chasing a rough idle before i realized the o2 sensors had bare wire.

my $.02

 

[tylambert]

Ive battled with PITA ass codes a bunch. WHat Ive found is basics, basics, basics.

1. Your O2 sensors need to be working. Front and Back. Check them with a resistance meter.
2. Post what steps youve taken from advice already given. Cleaned the intake, airfilter, airfilter, changed fuel filter. etc.
3. If you have run fuel cleaner thats good, i have gotten bad gas before. try a little ethanol free gas if you have it in your area from a reputable station (brand name like shell, not bobs drywall, groceries and gas)

I have always had terrible luck with o2 sensors, regardless of the codes, when i get a check engine light, if it is even close to related, i check it. I once spent almost a grand with a mechanic chasing a rough idle before i realized the o2 sensors had bare wire.

my $.02

Thanks! I really appreciate the help! I will check the o2 sensor tomorrow at school! A couple have led me to belive it could be something with my air intake.. my filter does need replacing and it would not hurt to clean my intake system because I did the deckplate mod but without the deckplate.. I have been offroad and in water also which kind of makes me t rhink it could have something to do with that! i have since then sealed the hole for good though..
Thanks again for ur help!