bhwrice

04 S4, 100k miles.

For the past few weeks I've been having an intermittent misfire. Some days car drives great, others I will have a serious loss of power and shuddering for a few seconds every few minutes. I have not been able to figure out any pattern (drive fine when its wet out).

However yesterday when I hopped in to drive home, I have a constant misfire, whole car shaking, maybe 20% power, blinking engine light. I turned the car off and on, same issue. I turned it off, opened the hood and jiggled the #2 injector and harness around a bit. Car started and drove home no issues.

Here are the codes:

16586 Cyl.2, Injector Circuit Fault in electrical circuit
16686 Cyl.2 Misfire Detected

I had it in the shop the other day for inspection, and the tech said he thought it was an injector. I just had the coil packs replaced about a month ago as well.

What could be causing such a random, heavy misfire, that would just go away? Is it possible the wiring is bad?

Comments much appreciated.

bhwrice

Any ideas? Do I just need to bite the bullet and start swapping plugs etc?

jrwstaples

I have had problems with my 2000 A4. The car began misfireing about a week after i bought it. VAG COM codes were: P0303 . misfire on cyl. 3 . swapped coils ...fine for a day ...swapped plugs. fine for a day then got way worse. Car drove like ****. Codes read again. lots this time... Bought ICM ebay for $50....very good deal. installed. drove 10 miles. CEL went off on its own. no more misfires. no bad idle.

It has been 15 days since i installed new ICM and so far no problems. Runs better than ever.


I was told i need to drop about 650 for all the problems and parts and labor. i have spent $90 on parts from ebay and about 20 minutes of my time to fix these misfires. DONT TRUST MECHANICS! its almost 2011 car motors are not rocket science!!!!!!!!

I AM NO LONGER THROWING ANY CODES.

s4master1

Calm down jr
they are rocket science, a 2000 a4 this days equals to a 77 chevy so don't get too cocky and don't confuse this guy even more instead of helping icm in 1.8 is as easy to figure as running out of gas
can you tell this guy where's the icm in his car?
let's try to gather more info and see if we can help

s4master1

very possible is in the wiring, when the ecm detects heavy load in a circuit it shuts it down and give you a fault for electrical connection
when is doing this misfire try moving the harness under the coolant tank and on the passenger side by the firwall
we see a few cases of wiring chaffing against the fasteners in the firewall
and cause overload in circuits
see if you can gather more info or any pattern like when cold/hot, turning or anything like that

tony1234

any update on this. I have the same code happening and ive switched injectors coils and plugs around and still occasionally this code comes back. I can wiggle the whole harness and it seems as if I can hear a slight misfire happen. but I can wiggle both sides and it happens

RallyVermont

How did your plugs look the last time you took them out?

Hart Media

Not sure if you tried these two things:
Heres some How To Videos if you need them.
--Replace the PCV Oil Separator:


--Replace Spark Plugs & Coil packs

When I replaced my coil packs the clips that clip into the coils was broken, so when I pushed the clips into the coil packs it didnt plug all the way into the coil, which caused misfiring starting from cylinder 1-4 with 4 misfiring the worst. If you look at the spark plug video you can see the space between cylinder 1 is closer than the space between cylinder 3 & 4. The fix was to pull the broken clip tab out of connector then the connector pushed all the way into coil. This is a common issue, that most mechanics are aware of but charge people for new coils. After they were connected properly the misfiring went away on all 4 cylinders. Hope this helps!!!

Hart Media

Not sure if you tried these two things:
Heres some How To Videos if you need them.
--Replace the PCV Oil Separator:


--Replace Spark Plugs & Coil packs

When I replaced my coil packs the clips that clip into the coils was broken, so when I pushed the clips into the coil packs it didnt plug all the way into the coil, which caused misfiring starting from cylinder 1-4 with 4 misfiring the worst. If you look at the spark plug video you can see the space between cylinder 1 is closer than the space between cylinder 3 & 4. The fix was to pull the broken clip tab out of connector then the connector pushed all the way into coil. This is a common issue, that most mechanics are aware of but charge people for new coils. After they were connected properly the misfiring went away on all 4 cylinders. Hope this helps!!!