2005 avalon cylinder misfire p0300 p0301 p0302 p0304 p0305 58,000 miles check engine

[kwirnu]

I was driving down a flat road at a constant 85mph with cruise control on. All of a sudden the check engine (orange figure) started flashing. I slowed down and pulled over. The temp was fine. I checked the oil and transmission fluid which were fine as well. The gas tank was 1/2 full. I went to Advance Auto and they checked the codes for me free of charge.

I had the following stored:

P0300 multiple cylinder misfire
P0301 cylinder 1 misfire
P0302 cylinder 2 misfire
P0304 cylinder 4 misfire
P0305 cylinder 5 misfire

I don't think it was the gas, but I suppose it could have been bad gas. It seems unlikely because I had used 1/2 a tank already.

I'll check the plugs tomorrow, but how would 4 plugs go bad all at once?

I'm thinking a computer glitch or maybe the coil. Not sure if these have multiple coils or not.

I let the car sit the afternoon and drove it home about 50 miles. The check engine light didn't light up and the car ran fine.

Has anyone had this happen to them in their avalon?

[inov8]

First and foremost . . . you are just inside the factory 60K mile powertrain warranty, so I suggest reporting all details, in writing, to your dealer. That way your complaint will be on record in case the problem suddenly gets worse at say . . . 61,000 miles. The dealer has access to the combined knowledge of Toyota techs worldwide; this could be a known problem.

I believe each cylinder has it's own spark coil.
Do you have a recollection of being near cross-country power transmission lines, or a TV/radio transmitter antenna, when the "check engine" light first came on?

[kwirnu]

In my experiences with the toyota dealer they know less than I do. I had to supply them all of the TSB's that I had fixed on my car. They couldn't even figure out the clunk sound which was coming from the front of the car was the engine mount they forgot to tighten. I dealt with that for 18 months until I saw the bolt sticking out of the mount.

[inov8]

It sounds like your dealer has a well-trained service writer. I worked part-time in a dealership
service dept. during my college days. These guys are trained to "play dumb".

Why? To avoid warranty work.

Isn't warranty work paid for by Toyota? Yes, but at unprofitable rates, plus the manufaturer will withhold dealer payment for any replaced/returned part they (Toyota in this case) deem to be "good".

But isn't low profit work better than none at all?
Not always. In addition to the aforementioned withholding of parts reimbursement, the manufacturers discourage warranty work by tracking each individual dealers warranty cost as a monthly percentage of sales. Dealers with a low percentage receive rewards, such as cash bonuses, free vacation trips, and preferential allocation of scarce popular models/colors/equipment packages.

The Service Manager's worst nightmare is a customer who visits only for warranty work and has his/her
own copies of relevant TSBs. The way to win is to convince you to go somewhere else (like the Toyota dealer in the next town who competes with them for sales).

Don't be fooled by good acting. You can be sure they have all of the TSBs just a couple of mouse clicks away.

[csaxon]

I agree with INOV8. If you have any part of a warranty left you had better get your problem in to the Toyota system. The flashing light indicates eventual potential damage to an expensive cat converter. What service was performed that they removed the engine mount bolt?

[kwirnu]

Originally Posted by csaxon

I agree with INOV8. If you have any part of a warranty left you had better get your problem in to the Toyota system. The flashing light indicates eventual potential damage to an expensive cat converter. What service was performed that they removed the engine mount bolt?

I'm not 100% sure, but I think it was the VVTI oil line fix. I had that done and then the clunk started soon after. I never connected the two. It sounded as if it was coming from the tire area.

[johnzillah]

Mine is doing the same thing. The engine sputters now while going up hill and sometime while driving on flat surfaces.I got a reading and it said all cylinders were misfired. My mechanic suggested replacing all the coils and that should do it. Do I need to replace all the coils? Please help!

[inov8]

I ran a search for the word "coil" in this forum and Edmunds, and found no reports of bad spark coils during the last 4 years. This suggests even one 2005+ Avalon spark coil failure is not a common occurence, never mind all 6 at once. It's theoretically not imp[ossible, but, like a full solar eclipse of the sun, I don't expect to see it happen often in my lifetime.

So, what else would cause multiple misfires under load besides defective spark coils? Here's some ideas; hopefully others will chime in with better ones.

The engine was pressure washed and water has seeped into the spark plug recesses.
There is (or was recently) an underhood leak, with similar results.
Bad gas, or gas with a high water content. Do you keep your tank always more than half-full during winter months?
Multiple ppark pluge are fouled. Do you do mostly city driving?
There is a malfunction in the Engine Control Module (ECM)
There is a wiring or connector problem betyween the ECM and the spark coils.
The transmission controller is holding the transmission in too high a gear (try manual downshifting, or disconnecting the battery for awhile to clear the adaptive memory).

Some other questions . . .
Was any work done on trhe car just before you first noticed the problem?
Did the diminished engine performance begin suddenly, or gradually get worse over time?

I would certainly try some tests and/or seek a second opinion before buying 6 new spark coils ($90/each retail; $68 mail order). The 3 closest to the firewall are labor-intensive to change.

[kwirnu]

I took mine to advance who gave me the codes free of charge. At the time the engine light was not flashing and the car seemed to run fine. I continued to drive the car maybe 100 miles and took it in to the dealer to check it out. They told me no codes were stored. the problem hasn't came back, yet.

Good Luck with your car. Maybe the problem will just go away.

[johnzillah]

I went ahead and replaced all my spark plugs and coils on my Avalon thinking that was the problem. The car ran fine the first 10 minutes and after that the problem came back. If anybody has a solution I am all ears. It has just hit 100K.

[johnzillah]

Just for those whoever have this problem I went and completly cleaned the batter terminals and filled the water capacity in the battery and put dielectric grease on the terminal heads. Afterwards I got a new air filter and blew off the Mass Air Flow sensor with a air hose. After I did that the check engine went off and the cars seems to be running fine now. I am going to trade this POS and get an Acadia or Tahoe!

[Tom in Tacoma]

Originally Posted by johnzillah

Just for those whoever have this problem I went and completly cleaned the batter terminals and filled the water capacity in the battery and put dielectric grease on the terminal heads. Afterwards I got a new air filter and blew off the Mass Air Flow sensor with a air hose. After I did that the check engine went off and the cars seems to be running fine now. I am going to trade this POS and get an Acadia or Tahoe!

The reason the check engine light went off is because you disconnected the battery. Give it some time to see if it comes back on before you jump out of the frying pan and into the fire.

[johnzillah]

It has been a week now since I did the work. Its good.