Check Engine popped on yesterday, 3 DTC Error codes

[jwicker]

2004 PreRunner V6 with 180,000 miles.

While driving, truck started to really run bad when under a reacceleration load. (When increasing speed from approx 55 to 65 mph)
Check engine light came on.
Auto Zone pulled the code (p0304 Clyinder 4 misfire).
Went to dealer and got a new set of plugs.

Put in the 3 on the driver side (in a hurry no time to pull the coil packs for the other 3).

Also found a ground wire bolted to the intake (on the driver side) that was very loose.

Truck ran great. No miss, check engine light went off.

Then again yesterday, check engine light pops on with no apparent symptoms (that I could hear/feel).

AutoZone pulled 3 this time:
P0031 - o2 - Bak 1 Sensor 1
P0304 - Cyl 4 misfire
P0136 - o2 - Bank 1 Sensor 2

My questions:
Could the misfire (oil pack, wire, plug, etc) cause both p2 sensors on bank 1 show errors?

Where is bank 1 and which sensor is 1 and which is 2?

I plan to replace the 3 plugs that I didn't do last time...but
Should I start throwing money at it with coil pack(s), set of wires, o2 sensors, etc?

Anyone have this specific mix of simultaneous codes and what did you do to fix?


Thanks
jw

[tex]

My old roomates Mustang had a misfiring cylinder once. The dealer replaced the coil for that specific cylinder and it ran great. If that coil is bad it could cause the problems with the O2 sensor because there is too much unburned fuel going through the exhaust.
I would replace the coil for the #4 cylinder and the other plugs and see how it runs.

[chris4x4]

A P0031 DTC trouble code may be caused by one or more of the following:

• A short or open in the heater circuit in the sensor
• A failed O2 sensor heater
• Wiring/connectors broken/frayed leading to sensor and/or relay
• Failed PCM/ECM

check for 12 volts at the heater circuit feed (hint: unplug the sensor and check at the wiring connector to do this measurement)
check the ground circuit for continuity
measure the resistance of the heater circuit (done on the sensor itself)
measure the resistance and voltage of the wiring



A code P0304 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

A code P0136 may mean that one or more of the following has happened:

• Faulty O2 sensor leak in exhaust close to O2 sensor
• Short to voltage on O2 signal circuit
• Open in circuit resistance caused by corrosion in connector

[kevhogaz]

Start with some factory plugs, and go from there. Almost every Toyota, and most every other import I see, with aftermarket plugs runs like crap, and sets misfire codes.

Since your P0304 set first, correct that one, and the others may not need to be addressed. Your O2 sensors are on the same side, bank one, so I'd guess the cylinder not firing is setting the codes for the O2 sensors.

[Hootbro]

As others have mentioned, I would start with a new coil pack. Also, if you got the extra coin, it would not hurt to change out both o2 sensors if they are factory originals. 180K is a good run on an o2 sensor and they can start giving you fits of intermittent failure before they go out.

[kevhogaz]

The coils do go bad quite often, and they're easy to check, if they're on the non-plenum side. It will be obvious if the spark is going through the boot.

[jwicker]

I picked up a set of OEM plug wires and 1 OEM coil.
Have not had time to put them on.
Checked gas mileage to see if it was extraordinarily low... and it was 18+ (half city, half hwy). Seems a little low to me... but first time I have checked it.

How do you guys feel about after market (Oreilly Auto) coil packs?
At $75, I ma considering taking the OEM coil back and picking up an aftermarket one.

The check engine light has not come back on since the day after my original post.

???????

thanks

[jwicker]

okay - this is getting rediculous.

Check engine light has been off since 6/29/09. I posted here yesterday asking about aftermarket coil packs...and 2 hours later the @$%! check engine light comes BACK on.

Stopped at Autozone again..... P0031 (02 Bank 1 Sensor 1).
Bosch OE type (Bosch part number 13613 $179)
Denso OE type (Denso part number 234-9001 $328.99)

Called dealer just to check price.... Denso OE item number 89467-35060 $236.71.... cheaper than Autozone, go figure.

Anyway.... I started looking online for better prices on Denso... found at:
http://www.trademotion.com/partlocat...&siteid=214074
For $166.34

So - I get in it to come to work this AM.... and the check engine light is OFF again.

WTF ?

I think I'll take back the OEM coil pack for refund, put on the plug wires and the other 3 plugs (passenger side) and see what happens.

[Hootbro]

I would be surprised if they take the coil pack back as it is usually considered an electrical part.

[jwicker]

The coil is unopened and was in-stock. They better take it back....I am quite crafty when it comes to revenge.

[jwicker]

Returned the coil pack.
Installed the new plug wires (OEM).
Installed the 3 new plugs (passenger side).
Seems to be running a little better (although it wasn't really running poorly).
No check engine light - YET.
After thinking about it..... it seems as though the Check Engine light would pop on when it was REALLY hot (ambient temp outside).

Anyone notice that before?
Or do O2 sensors seems to flag issues more when it is hot?

I had a Grand Cherokee that would pop an 02 sensor error when it was below 42 degrees and I let the truck warm up. It was an ECM programming issue.

Just wondering.
And updating.

[jwicker]

Well, found a local shop (honest and reliable) that offers free diagnosis (not just a code read - but a true diagnostic).

Dropped it off Tues night and picked it up Wed afternoon.

The o2 sensor (sensor 1 bank 1) is definitely bad - the heater is shot on it.

The tech/owner also mentioned that they were getting some weird and unusually high firing voltages.

He said that this is usually caused by a bad plug or plug wire...but since I just recently replaced all plugs and wires with OEM....it probably is something else and could be a product of the bad o2 sensor. He mentioned that when the oxygen sensor is bad, the mix is usually lean, the ignition has to fire at higher voltages to get across the resistance of the air/lack of fuel.

Anyone heard that before???

Anyhoo... he wanted almost $300 to replace the sensor. ($234 for the part and $50 for labor)

I ordered a new OEM Denso from Rockauto for $146 with free shipping after coupon code and it should be here in 2-3 days.

The CEL is still lit (comes and goes) and the idle is still rough...and sometimes surges a little at stop lights.... we'll see if the sensor fixes these issues.

I pulled the MAF from the intake tube and it looks clean.

Just an update.

[chris4x4]

Thanks for the update.

[jwicker]

Got the o2 sesor from RockAuto this AM.
I soaked the nuts a few days ago with PB Blaster.
With my 1/4' drive and a 12mm deep well socket, they were off andthe plug was disconnected.

Cleaned the seal surface with a wire brush.

After installing the new sensor, I disonnected the negative batter cable for about 20 minutes.

So far no CEL (fingers crossed).

I took it to Autozone to see if they could check for any residual codes and clear it (just in case disconnecting the battery cable didn't clear everything).
He said that he couldn't do anything unless the CEL was on and that the battery disconnect should have done the job.

We'll see.

Also picked up a Lucas Oil fuel injection cleaner and can of MAF sensor cleaner. Just in case. I noticed a little rough idle, but it seems to have more pep.

Just another update.