changed plugs, now lumpy idle only when hot
Thread Starter
New Member
Joined: Sep 2005
Posts: 220
Likes: 0
changed plugs, now lumpy idle only when hot
I recently changed plug on my 2000 A6 2.8 from the Bosch Platinum +4's that were in there to Autolite Platinum's. Now, when the car gets hot it starts to idle rough.
I am guessing its the plugs, and I bought the +4's to put in tonight, but when I was changing the plugs some of the thin, rigid plastic insulator around the spark plug wires cracked off. Any chance the wires are getting too hot without that outside plastic coating, and that's what's causing the car to miss?
98k miles.
I'm a lightweight - thanks for the help
I am guessing its the plugs, and I bought the +4's to put in tonight, but when I was changing the plugs some of the thin, rigid plastic insulator around the spark plug wires cracked off. Any chance the wires are getting too hot without that outside plastic coating, and that's what's causing the car to miss?
98k miles.
I'm a lightweight - thanks for the help
Member
Joined: May 2001
Posts: 6,211
Likes: 1
How many miles? Is that engine coil-on-plug, or plug wires? I would advise replacing the wires or
spark plug connector (if coil-on-plug) as it sounds like a bad connection at high temps. Don't forget - you go through the double whammy of thermal expansion and increased electrical resistance at high temps. Also, I've seen some plugs just not work very well on some cars. Personally, I wouldn't buy anything from Allied Signal (no Autolite, Fram, Bendix, etc). My company has been taken over by ex-Allied Signal execs, and they certainly know how to ruin products - reduce cost (quality) of materials of construction while keeping the illusion of quality and holding prices high to maximize profit. Many times at the customers expense, so to speak.
I've have good luck with the Bosch Plat +4 in my 2.8L 30V (in a 2000 Passat GLX - same as fwd A6 for the most part). Others hate Bosch and only go with NGK or Denso. I tried some Spilfire's a long time ago in a Mazda, and no matter what I did, they ran like crap - in the end they were just POS plugs; I liken the Autolite's to them - again, just my opinion, no real data. HOpe all this helps...
I've have good luck with the Bosch Plat +4 in my 2.8L 30V (in a 2000 Passat GLX - same as fwd A6 for the most part). Others hate Bosch and only go with NGK or Denso. I tried some Spilfire's a long time ago in a Mazda, and no matter what I did, they ran like crap - in the end they were just POS plugs; I liken the Autolite's to them - again, just my opinion, no real data. HOpe all this helps...
Thread Starter
New Member
Joined: Sep 2005
Posts: 220
Likes: 0
Tonight I replaced the Autolites
with Bosch Platinum +4's. Plus I wasn't using my torque wrench on Sunday when I changed the plugs (I know, I know). When I pulled the plugs some of them came unscrewed without using the ratchet attachment! Maybe this was half my problem...? Torqued em' down this time to 20 ft lbs.
Member
Joined: May 2001
Posts: 6,211
Likes: 1
Loose plugs can definitely contribute to lumpy idle. The deal on plugs is that the platinum tips
last longer, but they take higher voltage to fire. The older style copper plugs fire easier (lower voltage), but don't last as long. Since you are normally aspirated, I would think the +4's are fine - have run them in my Passat for 37k miles now with no problems whatsoever. At 98k, your wires are getting old and should be replaced. The combination of loose plugs and old wires would definitely account for your symptoms. If the rough idle/stumble goes away, then you should be OK for a short while but I would get new wires or connectors very soon to insure continued smooth operation.
Thread Starter
New Member
Joined: Sep 2005
Posts: 220
Likes: 0
HELP!!
Changed out the Autolite plugs and swapped for the Bosch +4's. Now, when the car gets hot, it misses and idles roughly. Its a lot better than it was before, but on a hot day (90's today) after 45 mins or so of driving, the check engine light started to flash. Its been on for a while - I assumed it was O2 sensors or something.
Could wires cause this? I know its not the tranny. O2 sensors? Can anyone tell me where I should start drilling down?
Thanks for everything
Could wires cause this? I know its not the tranny. O2 sensors? Can anyone tell me where I should start drilling down?
Thanks for everything
Thread
Thread Starter
Forum
Replies
Last Post
chenishead
A8 / S8 (D2 Platform) Discussion
8
Feb 22, 2009 08:03 PM
