Cylinder misfire codes. HELP!!!

tundraboy27909 · #1 (**permalink**) 11-25-2007, 02:27 PM

Anyone have any idea what to look for?
My 2000 Tundra started "missing" yesterday just after I had left the autoparts store. I had decided to replace the spark plugs (Denso K20RU OE replacement plugs). I thought that would fix the problem but it didn't.

I borrowed a code scanner and got PO306. I checked the coil and swapped it with another trying to determine if it was the coil. Same code. I cleared the code, unplugged the battery and reconnected the battery and started it up. It would not start. No codes though.

I disconnected/reconnected the battery and started it. It runs rough but did start and now gives codes PO300, PO301, PO304. What gives?? Any ideas what to look for?

Picasso · #2 (**permalink**) 11-25-2007, 03:56 PM

Since your symptoms are random among all of your cylinders, the cause is something that effects your engine as a whole.

There have been a few people that have reported similar symptoms on this board, but the causes elude me at the moment. Maybe someone else will remember. I don't recall them being major problems though.

The things that come to mind, in priority order, are:
1. Clogged fuel filter
2. MAF sensor, throttle body, air filter, and plugs (which you've already taken care of) need to be cleaned/replaced

A little more info will help to diagnose your truck.
- When were the above items maintained last?
- Has anything been done to your truck recently? (Mods, repairs, etc.)
- Are there any other symptoms that your truck is experiencing?

Paul

tundraboy27909 · #3 (**permalink**) 11-26-2007, 08:03 PM

I just cleaned the MAF sensor and it did not change anything so I will strike that one off the list.

tundraboy27909 · #4 (**permalink**) 11-29-2007, 09:45 PM

Finally had to give in and take it to the shop. Bad coil on cylinder 4.

Picasso · #5 (**permalink**) 11-30-2007, 07:55 AM

Quote:

Originally Posted by tundraboy27909

Finally had to give in and take it to the shop. Bad coil on cylinder 4.

You're the second or third person to have their ECU report random misfires caused by one bad coil pack. Very strange.

Do you know how the dealership found the bad coil?

Paul

tundraboy27909 · #6 (**permalink**) 11-30-2007, 05:41 PM

The code I pulled showed a cylinder 6 misfire. I swapped the cylinder 6 and 4 coils in hopes that the problem would transfer to cylinder 4 thus proving it was the coil. I could not get my scanner to to show that the cylinder 4 coil (previously cylinder 6 coil) was the problem. Evidentally it was as the shop said it was a bad coil on cylinder 4.
I could have saved myself a lot of money if I had gone with my gut instinct and replaced the coil that I thought was bad.

I got charged for the retail price of the coil ($90) plus diagnostic computer fee ($60) plus labor ($60).