My car is a '99 3.2 TL, 163K miles

On the drive to work yesterday, the car starting shaking badly when acceleration, idling roughly (thought it was going to stall), and the CEL & TCS came on, with the CEL flashing. I took it to the local parts store, and the codes came back as cylinder misfires. I tracked the problem to one of the ignition coils, replaced it, and the car went back to normal (I thought). I drove it a bit last night and it seemed normal, and went to bed proud of myself (not much DIY experience with cars here).

This morning, all seemed fine, until, pulling into a drive through, the car starting idling roughly. It still accelerated fine, but 5 minutes later the CEL and TCS light came back on. The car performs fine accelerating now, just idles rough. I haven't had time to get the codes read yet, but I suspect they're the same.

Any tips as to what I should be looking at here? It'd be a big coincidence for another coil to fail the next day, and the symptoms are different. I didn't change the plugs out yesterday, should I? It did get driven around with the misfires for 15ish miles yesterday; could that maybe clog up the EGR and set off some new codes? I'll update with new codes this afternoon when I can get them, but any advice or heads up from the forum would be greatly appreciated! It's been of immense help so far!

 

when you tested the coil packs, did you test all of them before replacing? or did you just replace one once you found it was bad? If you tested all of them already since the problem occured again, I'd go through and test one more time to make sure the others didn't fail, although very unlikely (also make sure the connections are tight/snug to the coil packs; as in torquing and tightening them down).
Next, I'd swap out all the spark plugs (to NGK Iridium IX!)as well if you haven't already as that can cause this problem as well, although usually it is the coil pack. But, since you said you haven't swapped the spark plugs yet, I'd definitely do that.
Then, I'd hit the EGR port with carb cleaner and a hanger (plenty DIY on the site for this) This will definitely get rid of all the gunk and build up there and clean your intake manifold area as well since you will be hitting the EGR.
Hopefully this will let her breath a bit better and clear up your problems. Hope that helps, keep us updated!

 

Mini update: Got the codes checked and they're all the same as last time (misfires on all cylinders except 1, which is ironically the one that was bad last time). I've bought the new plugs and will get to it a little later this evening and keep the thread updated.

 

Final (Hopefully) Update: When I changed the coil pack yesterday, I did check all of them. I know this because the bad one was the last one I tried (I think it's actually #3), and I was getting worried that it was a different problem. Anyways, I took the advice offered and ran through the test again, and disconnecting the #2 coil didn't drop the rpm, so I swapped it with a good one and voila, things are back to normal.

It seems unlikely for two coils to fail a day apart, but I suppose it could happen. I think I'll buy an extra and keep it on hand. That way it'll be years before another fails.

Thanks for the tip!

 

Nice! Glad it was an easy fix. And it does seem unlikely for two to fail that quick, I guess anything can happen haha

 

just the other day a ziner reported a prior dual coil failure, odd but true

did you reset the ECU by removing the CLOCK fuse on passenger end of dash for a minute then put back in
clears all codes and ecu does a relearn- cks all systems- clock fuse is the SECRET BACKUP POWER TO ECU = easiest way to reset ecu after work because of codes is done

 

Just in case anyone else is ever in in the same boat, I'm updating this to say that today a third coil failed. That's 3 within 250 miles if you're keeping score.

And yes, I did reset the ECU by pulling the clock fuse.

 

this is a 99 with 160~ kmiles correct?
was there recent spark plug repleacement, or other thing that would have hurt coils like weak battery grounds causing arc?
was oil blowby from loose spark plug on bad coil cyl involved in this car?

what coils are you installing- OE new, used or aftermarket? price?

 

reading mugens post- do I understand= these were original spark plugs? you mean the coils had to generate power thru a lot of residstance and general dislike by plugs of operating more than a lifetime and a half!