I have a 98.5 A4 1.8TQ that has been having a CEL flashing and a severely rough idle + hesitation acceleration problems (it's barely drivable right now). I did some research and found out that it may either be the Coil Packs or the Ignition Control Module that could be causing my problem. That's at least what the majority of the searches I did led me to believe. I'd rather just try to change the coil packs myself first(cause they're cheap) rather than taking it in for a diagnostic fee which costs more and doesn't really do anything or they could lie to me. Can someone help me out on where to buy the cheapest one's available for my specific car, and how to replace them? (where they're located in the engine etc.) I'm not the best with cars, (pretty much a noob) but I am very inclined to keeping my car working throughout my college years. I also read that I might need to buy two. I'm confused. Please someone help me.

 

Have you verified that your plugs are OK? Not only the right type, but also gapped correctly? They should be, I believe, .032" gap for a stock tune, or if you have a chip, you should gap down to .028". If you're gapped incorrectly, it could cause the misfire. Verify that you are running proper plugs, gapped correctly, and that they're in good condition, and if you doubt any of those things, go ahead and change them first. If the problem persists, look into coil packs.

 

Easy way to determine if its a coil pack is to start your car up and start unplugging the coil packs, one at a time, if you get a change in idle then that cylinder is sparking, if you unplug a coilpack and there is no change in idle, thats your misfiring cylinder. Change the coil pack and plug between that cylinder and one that is sparking. If you still get a misfire on that cylinder then its your ICM, if it moves with to the other cylinder then its your coil pack.

Edit: Cheap place to get an ICM is ebay, picked one up last week when my car was misfiring on cylinder one. Expect to pay about $70 shipped regular mail and $105 one-day.

Your coilpacks are located directly under the Engine cover, use a phillips or a quarter to get it off, it uses pop up screws, there will be 4 black "packs", you use an allen wrench to remove the packs. You can also disconnect the connection, by using a flat head to pry the clip up. The spark plugs are located in the block beneath the coil packs. ICM is located on top of the airbox, one side has a 5-prong connection, one side is the 4-prong connection. If you have a '99 or below, I'd bet its your ICM, coil packs normally don't go out on 99s and below because the ICM function is seperate from the coilpack. Audi made a change in the ignition system in 00 where the ICM is built into the coilpack, which is why you see more failing coilpacks on 00+.

 

Hey thanks holister, so just to get this straight, are there 4 different coil packs that I MAY have to replace? And this ICM, how hard of a change is it?

 

Yeah instead of a distributor system, an a4 uses whats called a "coil on pack" or COP system, basically one coil pack per cylinder, so in your case it will be 4. The ICM is easy, about a 10 minute job tops, and thats if the bolts are stripped/stuck. Basically you just unscrew two hex bolts, remove the connectors by pushing the metal bracket in, then replace and install the bolts. Its locatedon top of the air box where the air filter goes. Theres a couple of sensors there, youll be replacing the one that has a 4-prong on on side and a 5-prong on the other. Says Bosch on top.

 

can someone verify that this is the correct ICM for my car? My car is a 1998.5 1.8TQ btw http://cgi.ebay.com/ebaymotors/VW-Pa...spagenameZWD1V Thanks!

 

Yeah that will work fine.

 

I got it scanned at autozone and this is what I got.

P0332 - Knock Sensor 2 Circuit Low Input (Bank 2)
P0302 - Cylinder 2 Misfire Detected
P0134 - O2 Sensor CKT No Activity (Bank 1 Sensor 1)
P0103 MAF or VAF A Circuit High Input
P0301 Cylinder 1 Misfire Detected

What could these codes possibly mean? Could it still be the ICM? Thanks for your input.

 

any ideas?

 

Yo, those codes mean you are missing, the knock is showing that there is a vibration and the o2s are throwing codes because they are getting a reading the cant fix in fuel trims due to the misses. Just replace the coil packs I work on them so yeah the coil packs on the older cars crap out all the time, and dont be cheap and just buy two of them because if 2 failed it will only be a matter of time till the other two fail.