March, 5, 2007 AT 5:07 PM

I have a 2000 Toyota Solara SLE V6 (3.0L), approx 130K miles.
Earlier today, the car began to run very rough at idle, and the Check Engine Light came on moments later. I scanned the codes and came up with P300, P301, P303, and P305. These are random cylinder misfire, and misfire on cylinders 1, 3, and 5 respectively.
The problem has replicated itself since, and typically all four codes appear. Cylinder 3 misfire appeared by itself on one occasion, and Cylinders 1 and 5 appeared by themselves at another time. The CEL flashes steadily. All the misfires have been confined to the rear bank.
I have cleaned the MAF, changed the fuel and air filters, and also all three A/F sensors. I have also tested with new plug wires (I have three plug wires that interface with the ignition coils).
I plan to change the plugs just as a baseline, though I did replace them about a year ago.
Finally, I will be testing with new ignition coils tomorrow.
I understand that a bad ignition coil can register multiple cylinder misfires - but since each coil interfaces with both front and rear banks, is this the probable cause (as my codes are restricted to one bank)?
I have also been advised that this problem could be related to the ECM or the fuel rail.
Beyond changing the plugs and ignition coils, I am unaware of how to troubleshoot this further. I am also unaware of what problems these vehicles are typically known for.
Any advice you could provide would be GREATLY appreciated.


Engine Miss


3 Answers



March, 6, 2007 AT 2:33 AM

The P0300 code is a random misfire code while all the other misfire codes denote a misfire problem in a specific cylinder. The last digit in the code tell a misfire in cylinder number one.

If a misfire in a specific cylinder should lead you to check the spark plug, fuel injector and compression.

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

Check all of these and you'll run right into your problem area.

HTH-Good Luck!



January, 11, 2014 AT 5:03 PM

Hi there

I have had a very similar issue!

One day my Solara just began misfiring, and loosing power on takeoff. The misfiring was particularly apparent on low idle! The engine light appeared soon after.

I decided to change the spark plugs. I did the three on the top of the engine first. I then tried the car and there was no change. I went behind and tried the cars back right plug, so as I look at the engine, the back left. I then tried the car again. This time it was much better, The engine light was off now and it was running smoother, but not yet was it ideal. I took the car for a quick spin and the power was improved when there wasn't a misfire but there was still a little shudder. It was at this point that I decided to change the last two hoping it would fix it completely.

At this point it took the car for a spin. It is more powerful however it still misfires on low revs and the lack of power can kick in if acceleration is to heavy.I noticed that the back three cylinders had plugs that were dirtier, indicating that they are the main problem, making this sound very similar to your problem.

Did you fix your problem. What was it?


solution man

March, 19, 2014 AT 6:39 AM

I had same problem calf. Speck. Avalon. I changed my air fuel sensor rear bank, plus my pcv valve was cloged with old oil gunk in the manifold section under the valve cover. Cleaned replaced a/f sensor and plugs car runs like new no more mifire on rear bank cylinders.

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