ok, im sure this has been asked several times before, but I'll ask again because I don't feel like searching through pages and pages of posts to find my answer.

About 6 months back, I was having a misfire issue (missing/backfiring on acceleration above 3000rpm). I took out the ****ty bosch plugs and threw in the ngk plats that should have been there in the first place. Problem fixed. Just this week, the misfire came back, this time with an idle misfire as well.

My question is, is this coils? My guess is that coils were dying all along and the new plugs were a band-aid fix until the coils deteriorated enough to cause the misfiring once again.

The only code that was ever output was a misfire on cyl 1 before i changed the plugs. This time, no codes.

Also, date of birth of the car was 12/98 if that helps.

Adam

 

Yes 99's are notorious for bad coil packs. You can buy some from a junkyard off of 95-98's pretty sure they are interchangeable. You should change all 6 while your at it

 

id recommend first, before going out to buy the damn coils, to unplug each one to see if the car reacts to you unplugging them...if one of them DOES NOT react (IE: the car does not bog down a little) the i would suggest taking out that coil pack and putting a good one from another cylinder in there. once u do this, unplug the one u just changed (unplug the coil in the cylinder that was misfiring) and if it still doesnt do anything, then its clear that in that cylinder, you have a bad injector.

Just happened to me not even 2 days ago!

good luck and let me know what happens

 

Put new coils in your 99. They are notorious(sp?) for failing on the 99's.
It made a huge differance in performance when I swapped the coils on my 99.
I had the same issues, misfires under a load, starting around 3K RPM's along with a "bump" in the idle at times. The car runs excellent with a new set of coils.

 

yes but at the same time, why change them if they're still good. Coil packs went bad in the 99's so bad because there was a TSB at one point for the leaky valve covers. oil leaked into the cylinders, causing many of the coils to go bad quickly.

Check your coil boots, and if they have a brownish ring around the boot, then be prepared to replace them soon.but dont just replace them all...like i said try the method aforementioned, and then if its not the injector, change all of them at once.