Misfires after changing all spark plugs and coil packs

[dainfamous]

Hi,

I get random misfires after changing the coil packs and spark plugs.
What else should I look into?

The car is APR stage 1 with approximated 75k miles.



Thanks.

[bacillus]

Spark plugs gapped correctly?

[TBomb]

Spark plugs gapped correctly?

For what it's worth, you might check the gap but don't try to change the gap, as you stand a high chance of damaging the electrode on the plug itself.

With 75K miles and fresh plugs and coil packs my guess would be intake valve deposits You have random misfires meaning not just one cylinder? Did it start before you changed the plugs and coil packs, or after?

[Krieger]

missfires in which cylinders and how often?

also, at idle, wot, cruising?

bit more info.

@tbomb, that's old school thinking. You can easily change the gapping, just don't be retarded and slam a coin or something in there and start bashing away. lol

[dainfamous]

Thanks for the responses.

I didn't perform the install myself.

Prior to changing the coils and plugs I gotten a misfire in one of the cylinders (thinking number #2) which caused a CEL. So I proceeded to have everything replaced (plugs and coils) for precautionary measures.

Its been 3000 miles since the change and I still get intermittent misfires not enough to cause a full blown CEL though once I did see my CEL light flashing while under WOT and disappeared after I let off the pedal.

It doesn't happen all the time. At times its smooth as butter.

Thanks.

[YoungMedic]

bad fuel injector

[Krieger]

idk about the injector there... id be more thinking along the lines of poor gap, a bad coil or plug, or carbon. injectors tend to run bad all the time if they are bad.

[YoungMedic]

mine didnt, intermittent misfires on cyl# 4, replaced plugs and coils, still had misfire and cold start misfires. pulled the #4 fuel injector and found it caked with carbon. replaced injector, ran like a champion and no more cold start misfires. did this at 68k miles

[Dabpy]

mine didnt, intermittent misfires on cyl# 4, replaced plugs and coils, still had misfire and cold start misfires. pulled the #4 fuel injector and found it caked with carbon. replaced injector, ran like a champion and no more cold start misfires. did this at 68k miles

How big of a job is it to pull the injector?

[YoungMedic]

it wasn't too bad, if you google Stasis k04 install there is a nice step by step on how to pull the manifold. Took me about 2 hrs to pull it, and an hour to get it back together, first time. And there are specialty tools involved

[gmikel]

it wasn't too bad, if you google Stasis k04 install there is a nice step by step on how to pull the manifold. Took me about 2 hrs to pull it, and an hour to get it back together, first time. And there are specialty tools involved

check the tools rquired as i forget the size of the triple square for the manifold support. don't start until you have on that is at least 4 inches long. you can't run to the store and buy one and you'll save yourself a lot of frustration. they are available at ecs and other vendors that advertise here.

[StuMacLean]

Long shot theory here, but I've seen B5 S4s have oxidation on the wiring to the coil packs. My friend chased a misfire for a year before finding that the connections on the coil pack cable was oxidized.

Could be worth taking a peak.

[jpawl]

Jumping in here.

Not much to add other than my frustration over the CEL after new plugs and coil packs.

Check engine light at 69.5K miles. APR Stage 1 flash over the last 59K or so.

Independant garage replaced spark plugs and coil packs and sent me on my way. CEL came back on as soon as I left. VAG-COM'd that night. Cyl 4 tripped it at a very low RPM. Reset light, same thing, cyl 4 trips it on a cold start up at low RPM (under 1800).

I have since changed back to program 1 (stock) to see if that would help. I have the same CEL coming back. The garage is thinking that maybe a BG intake cleaning service will help clear up with what we both think is a carbon build up in the intake area due to the direct injection. I have read mixed reviews on it.

Jim

[OEMplush1]

I had flashing cel light after doing same changes, I added catch can and removed plastic PCV and my boost issues went away.

[Weelildubb2.0t]

I have since changed back to program 1 (stock) to see if that would help. I have the same CEL coming back. The garage is thinking that maybe a BG intake cleaning service will help clear up with what we both think is a carbon build up in the intake area due to the direct injection. I have read mixed reviews on it.

Jim

I heard the same thing about the BG intake cleaner, if the BG service is a lot of $$$ I'll just skip it and go right to manual valve cleaning

[rboss101]

My car started experiencing misfires after changing the sparkplugs. Never happened before. Now it gives me a code for random misfires and #4 in particular. Today is the second tome it happened after starting the car on a cold morning. Second time 2 weeks after changing spark plugs. Just after I start, when its still cold, and never during driving or idling when warmed up. Strange. Could it be the plugs. I am using the new NGK ones. NGK Part # 1675 Laser Platinum pre gapped. Didnt have a problem with this before. I think these a are one range colder than the previous ones I had in the car. Could that be the problem?

[ROH ECHT]

Unexplained random misfires usually turn out to be carbon build up. Not so much a prob for newer motors, but yes this happens to be the more common culprit;
I clean every 10k miles. I made a vid;

http://www.youtube.com/watch?v=ykenBjJ8XZM

[bkpapi12]

same thing happened to me after changing to red coils + new plugs. 2 cylinders with random misfire's cleared codes, squeezed connectors on coils + plus gentle tap on coils. 800 miles later cel free. hope this helps