2000 LC Misfiring (1 Viewer)

[Venicetiger]

First off. I have been a long time lurker and would like to say that this is a great forum.

Problem: My 2000 LC with 147,000 miles has just started running rough. Ran a scan and got the code for a bad OS. Due to work, I did not immediately replace the OS and continued to drive it for a couple of weeks. During this time, the CE light and the VSC light came on and it started running very rough.

I changed the OS and disconnected the battery to clear the CE light. This worked for about 5 minutes and then the CE and VSC lights came back on. I have just ran another scan and the OS code does not come up, but misfiring codes on 5 of the cylinders shows up 300, 302,303, 304, 306.

Where should I start? Replace the plugs or assume a bad coil?

TIA.

 

[campoj2]

I would suspect that you have at least one misfiring coil pack - they are about $80 each from CDan. They are not hard to put in if you can get to the pack basically 2 bolts and you're done.

 

[Venicetiger]

Thanks for the reply. I suspect this as well. Bought NGK Iridium spark plugs yesterday and am installing this morning. It has been about 70,OOO miles since last SP change. If that doesn't do it, I suspect it will be a coil pack.

One question. Do the NGK Iridium plugs come "pre-gapped" ?

Thanks.

 

[campoj2]

They should come pre-gapped, if you have a gapping tool it will take a few minutes to verify.

 

[pint]

Coil pack. Mine did this at about 110K. Ran perfect the day before. Started up and ran reeeeally rough the next morning with major loss in power. Threw in a coil pack and all was good! It took about 10 minutes to swap out.

 

[Venicetiger]

Yeah. I have changed all of the plugs and it is still running rough. I don't know which coil might be bad, so I guess I will start at one and test thru 8.

 

[campoj2]

Doesn't your code scanner tell you what coil pack it bad??

 

[NMuzj100]

If you go to the FAQ thread on Coil packs and with the cylinder map you should be able to figure out which one it is. The misfire sensors are so sensitive that the sensors adjacent to the problem cylinder also register a misfire.

Scratch that, there is no link for a thread like that in the FAQ ... Just this little one I whipped up.

Rough Idle/Sputtering/CEL/Misfire = Coil pack problems

The codes translate to Random/Multiple Misfires on cylinders 1,2,3, and 5. My guess is #1 (front left) or less likely #3 (second from front left).

 

[Trunk Monkey]

Scratch that, there is no link for a thread like that in the FAQ ... Just this little one I whipped up.

There is now, thanks!