P0302... Please Advise I am getting frustrated

[4runnerTiger]

My experience so far with my truck has been quite love hate...

It seems that everytime it runs beautifully for a few weeks something else happens.

I love the forum but sometimes its like information overload and it scares the crap out of me.

So - if anyone can please advise.

I drove the 4runner this morning and everything was perfect.
This afternoon at lunch it ran VERY rough. Smelled like unburnt gas etc.

Symptoms: 1. hesitant off throttle
2. Ran fine in park idle at 8-900 rpm
3. Idle was low 600 rpm in drive
4. CEL came on
5. Down on power
6. Some vibration

It threw a CEL and a P0302 and P0133 came up. I assume the PO133 was caused by the P0302.

I did some searching and it appears that most people replace spark plugs and or wires to fix this.

However, most people report this not fixing their issues.

I have not currently done anything.

It seems most people either replace an injector or it could be a worn timing belt.

Now I dont know what to do? What to test etc?

Any help guys would be very much appreciated....

 

[SliderNH]

My experience so far with my truck has been quite love hate...

It seems that everytime it runs beautifully for a few weeks something else happens.

I love the forum but sometimes its like information overload and it scares the crap out of me.

So - if anyone can please advise.

I drove the 4runner this morning and everything was perfect.
This afternoon at lunch it ran VERY rough. Smelled like unburnt gas etc.

Symptoms: 1. hesitant off throttle
2. Ran fine in park idle at 8-900 rpm
3. Idle was low 600 rpm in drive
4. CEL came on
5. Down on power
6. Some vibration

It threw a CEL and a P0302 and P0133 came up. I assume the PO133 was caused by the P0302.

I did some searching and it appears that most people replace spark plugs and or wires to fix this.

However, most people report this not fixing their issues.

I have not currently done anything.

It seems most people either replace an injector or it could be a worn timing belt.

Now I dont know what to do? What to test etc?

Any help guys would be very much appreciated....

If it smells like unburnt fuel and its down on power, The first thing I would do is check the spark plugs and wires. To me it sounds like one of the cylinders or a couple of the cylinders aren't firing. Testing the plugs and wires: Pull each spark plug out one at a time, connected to its corresponding wire, crank over the motor with the spark grounded to a metal surface(will take 2 people), and you should see a small spark each time the motor turns over. If you do not see a spark in all of the cylinders determine whether it is a bad spark plug, or a bad wire by moving the plug to a different wire (one that you know is firing) What exactly do the codes P0302 and P0133 mean?

 

[pauls4runner]

P0133 is heated oxygen sensor circuit slow response. the rear main seal on my 98 V6 has a slow leak and the buildup of oil was running down different lines and crevices and eventually led to a build up of oil on the plug harness for the up stream heated oxygen sensor. I havent had time to replace my main seal yet so I clean up the oil every week or 2 and I also replaced the oxygen sensor. so far Im going on 3 months with no P0133, and it was coming on every 2-3 weeks.
P0302 is cylinder 2 misfire. their are several things that can lead to a cyl 2 misfire. The most common would be a fouled spark plug, faulty plug wire, faulty ignition coil, or leaking sparkplug tube grommet allowing oil to seap onto the spark plug. more drastically, bad piston rings, bad piston, crack in the heak, crack in the block, bad head gasket can all to an extent cause a mis fire as well!