2000 Tundra Misfire Problem

00Tundraman · #1 (**permalink**) 01-08-2008, 04:39 PM

Hey guys im stumped,

the other day driving down the freeway the tundra started to rattle and loose engine power. check engine light started flashing. the next day i got it hooked up to a scanner and the codes read that number 7 cylinder misfire, along with my two front faulty o2 sensors.

So right away i decided to look up on TS that particular code to see if anyone has had the same issue. and sure enough a few people had a coil issue.

but first things first i figured the spark plugs have never been changed so i picked them up first. Which did nothing. the old ones where on there way out though. the spark plug was autolite and they were supposed to be same as oem, according to the napa guy.

After two days of searching i found an ignition coil and replaced the #7 cylinder ignition coil. (driver side closest to firewall.) started her up and seemed no difference. hooked it back up to the scanner and showed code p1340 and the scanner said "see service manual" but found through TS that the code means Igniter Circuit Malfunction No. 8.

after this i took the brand new coil and one by one replaced each cylinder and then if no change i would put back the old one and move on. so after all 8 cylinders nothing changed.

right now the only code that is displayed on the scanner is the P1340.

still i can tell some cylinder is misfireing. not sure why though.

any possibilities?

thanks.

ddvk · #2 (**permalink**) 01-08-2008, 04:56 PM

Honestly there is no way to check for faulty coils. If you are on a budget, get NGK plugs (not some cheap Autolite stuff) from the stealership and replace all of them. While you are at replacing the plugs, use 3M electrical masking tape and cover the entire coil to provide insulation... stop gap arrangement. It will take the coils thro the winter..

You need to invest in new OEM coils sooner or later..

kathyricks · #3 (**permalink**) 01-08-2008, 05:32 PM

Quote:

Originally Posted by 00Tundraman

the other day driving down the freeway the tundra started to rattle and loose engine power. check engine light started flashing. the next day i got it hooked up to a scanner and the codes read that number 7 cylinder misfire, along with my two front faulty o2 sensors.

What underhood mods did the engine have BEFORE the misfire? List EVERYTHING that is aftermarket; e.g. spark plugs, air filter, coils, oxygen sensors, headers, and so forth. As a starting point we need to know if we are dealing with a stock truck or not.

Also, how long and far did you drive with the misfire?

00Tundraman · #4 (**permalink**) 01-08-2008, 07:28 PM

completely stock. and drove about 3 miles to get home.

mustang67408 · #5 (**permalink**) 01-08-2008, 08:58 PM

Once you get a misfire code, you have to clear the code then retest.

If there is a misfire and a code and you swap the coil, it is going to have a miss no matter what, until you clear the code and try again.
The ecu shuts down the cylinder with the problem to prevent further damage. THis is a pain but works.

p1340 is for a bad Igniter/coil cylinder #8, or bad wire harness, or a bad ECU. I have attached a diag pdf for you to follow and see what you can come up with.

First thing I would do is get some NGK or Denso Plugs
2nd thing is clear code with new coil in cylinder 7 and see how it runs
see what code resets, if it is p1340 then do the diag from the PDF
Check all the wiring around the intake manifold carefully, rodents like to eat wires and use the insulation to stay warm, this can cause many issues.

ddvk · #6 (**permalink**) 01-09-2008, 10:21 AM

Honestly, if a coil starts to thro codes (becoz insulation of 33KV DC broke down within the coil by using cheap plugs), then the others are on their way to the graveyard. So don't waste your time identifying/root causing the problem..

1) Change plugs and coils
2) Replace fuel filter and get a fuel injection service done.
3) Save up money for a failing cat and pre-cat down the lane, thanks to fuel dumped with faulty plugs/coils. BTW, this is the first time I heardthat cylinders will get shut off with coil related SES codes (you could expect that from a Mercedes not from average joe's vehicle).

Good luck.

00Tundraman · #7 (**permalink**) 01-09-2008, 05:14 PM

mustang thanks alot for you help were going to take a look at it tonight. yesterday i looked at cylinder 8 and the harness that plugs into the coil had a wire sticking out of the top of it looked broken. so this is most likely the problem. thanks for your attachment that will come in handy.

tundraman

drhartley · #8 (**permalink**) 03-13-2008, 04:49 PM

Along the same lines...after my muffler blew a hole in it, the engine is running really rough. I changed the plugs (Bosch, and muffler of course) and looks like cylinder 7 isn't firing due to the dirty plug while all the others look normal. Changed the 7 coil to other side and now it's really rough. Gonna change coils back as now the Advanced Auto diagnostic says cylinder 7 AND 6 are misfiring. So, looks like I should next get new wiring before getting new coils (mucho $$) for those, and then what? Does anyone know the cylinder configuration, what cylinder is what number? I know #7 is the driver side/firewall from this forum but the others...????? Please help!

csfisher · #9 (**permalink**) 04-02-2008, 05:45 PM

I had a misfiring problem and it turned out to be the injectors. Replaced all 8 and it works like a dream now!

mustang67408 · #10 (**permalink**) 04-02-2008, 05:56 PM

Quote:

Originally Posted by csfisher

I had a misfiring problem and it turned out to be the injectors. Replaced all 8 and it works like a dream now!

WOW.. There's a first. I would have never guessed all 8.
Glad to hear she is purring like a kitten now.

Excellent job at sticking with it.