Code P0306 Misfiring on cylinder #6 (1997 LX450 with 304K) (1 Viewer)

[bj70alex]

After starting the truck and driving for a couple miles i notiiced that it's not running like yesterday, shaking, vibration etc. I asked my friend to come and check it.
He pulled code P0305. Now my question is, go with OEM or Replacement Injector? If replacement, which one would you recommend. Thank you

 

[ajax1]

Oem from good source

 

[bj70alex]

Oem from good source

Thank you. Correction. Code is P0306, not P0305............

 

[Kernal]

@bj70alex: did it do this once then clear up or is it still running rough now?

There are a number of reasons for a misfire, from contaminated gasoline to a leaking head gasket.

Did you get fuel just before the rough running started?
Has work of any kind been done on the engine recently?
Has the engine been touched, washed, or fiddled with in any way before this started?
Is routine maintenance up to date (air filter, spark plugs, distributor cap/rotor, fuel filter)
Have you gotten that same code or other codes (multiple misfires) previously?
Has the engine been consuming coolant (drop in the radiator or coolant reservoir level)?
Has the engine been running hot or overheating?
Have you seen clouds of sweet smelling exhaust fumes?

@bj70alex: try to answer each of those questions.

 

[Comet]

Subscribed.

 

[Shipwreck]

A common reason for a PO306 code is a failure of the injector connector itself. The heat at the rear of the engine causes the plastic to become brittle. The little locking tab often doesn't click in place allowing a loose connection. The wiring feeding the injector is also prone to heat damage.
IF you do find a bad connector, it can be replaced easily with either the plastic connector only or with a connector and pigtail.
90980-11153 OEM replacement connector
82999-12790 connector with pigtails
Lots of other non-OEM options as well.

Pro tip: when replacing just the connector, put the old one in a plastic bag and crush it with pliers or a hammer. The pins will remain intact and can be inserted into the new one. No special removal picks needed.

 

[Malleus]

x2. I would not buy a new injector until I was absolutely positive the problem was not in the harness, especially on Cylinder #6.

FWIW, the factory connector housings are light grey and brown, alternating between odd and even cylinders. You can only get new grey replacements, but they are the same connector housing.

 

[CharlieS]

Ballinger Motorsports sells the connectors for a very reasonable price, both with and without pigtails. I think the ones I got were brown, not that it matters.

 

[Malleus]

That's good to know. Maybe they have the brown stock Toyota doesn't have.

 

[LecheFidelis]

Just had this happen to me as I was doing the heater control valve. The connector for cylinder 1 fuel injector was broken and came loose when I moved the engine harness. Right now, I just put it back where it goes, and the misfire went away. Will get around to fixing the connector in a couple weeks.

 

[lumbee1]

I had a P0306 as well and the truck was running rough. Mine was due to this: