You might also carry a can of refrigerant/freeze used to test electronic parts. When you get a misfire, spray/freeze the ICM(s) and see if the misfire goes away.

But chances are you've already identified the problem if you have no or hardened dielectric grease under your ICM (well, between the power transistor and the heat sink). If you have some dielectric grease suitable for automotive heat sink use, try replacing the grease.

I cooked an ICM (power transistor) on a saab 900T by failing to cover the ICM with a plastic bag or tin foil wrap when cleaning the engine with gunk. Once burnt, twice shy.

I should have mentioned that in the midst of all the other repairs... Yes, I took the ICM's off the airbox cover. Thouroghly cleaned and reinstalled them with heat sink compound. I also dielectric greased all electric connections upon reinstall. Great idea on the refridgerant!! I was gonna take it to my shop/garage tomorrow and try a different approch. I was thinking of heating each ICM seperately with a blow dryer/heat gun to try to reproduce the misfire. Any ideas on that??

I've done the copy codes when misfiring, clear and recheck. Weird thing is after clearing the codes, the misfire doesn't go away... and the CEL doesn't come back immediately, and no new codes appear. I have to drive it for a while before any codes show up. I think I really need to invest in a full VAGcom software and learn how and what blocks I need to read. This is getting tiring. It seems as if the more parts I find bad and replace due to being old / worn the worse the misfire is when it shows up. When this car is not misfiring it is a dream to drive. Especially after replacing the bad parts last weekend, it has sooo much more power. But then it starts this misfire BS...

Yes, if you don't have the full VCDS, you are screwing with a condom (with a hole in it.)

Looking on the Ross-Tech website now... I have the laptop, serial cable and OBD2 adapter. The adapter has a 2 position switch on it. After searching the Ross-Tech site, I'm thinking the software I have is the free version. What is everyone's opinion on which software I should get? I will continue owning Audis and my wife-to-be drives a 2008 VW. I can make good use of the code reader as I do my own repairs. I'm thinking the lite version @ $99.

After reading the chart showing the functions of VCDS and VCDS-Lite, I would think that you could get away with the Lite version, as long as you don't change laptops. That said, the $350 that I spent on the HEX-CAN cable has paid for itself many times over in diagnostics. As a matter of fact, the first time I used it, I was able to diagnose a weird problem that had stumped several shops (a bad circuit in the ECU was flipping a bit on an O2 sensor heater circuit, showing it open when in fact it was in spec.)

Okay, looking at my DTC from when I cleared it after performing the last set of repairs. I looks as if the missfires have moved from bank 1 to bank 2. Bingo, ICM!! Here's the kicker, I didn't mark them before removing, cleaning and resetting them on heat paste... Which one is which? Looking at the airbox from the passenger fender, there is one closer to the front of car and one towards the firewall.

VCDS
 

Georgeb944, thanks for the reply. What is the difference with your HEX-CAN? Is it software access or is it the cable/adapter? There were a couple options, some very expensive down to $99(Lite). I'm wondering what the upgrades above the Lite version would do for me as a weekend warrior.

Basically, the HEX-CAN is a cable that will work on any VAG car with OBD2 from 1996 to current and will provide diagnostic interpretation of error codes and Service Reset (SRI) for all years. VCDS-Lite will only provide interpretation to around 2006 and no SRI. If you can live with those limitations, then save a couple hundred bucks.

First, before you make any $$ decision, check to see if VCDS-Lite will work with your wife-to-be's VW. If it doesn't work without registration, it probably won't work after registration.

Black connector is cyl 1,2,3. Brown connector is cyl 4,5,6.

Thanks for the reply again, just drove car w/ VCDS on, metering blocks 014, 015 & 016. Took about 5 mins driving and then 5 mins idling, #3 on 016(cyl6) started counting. I sprayed with compressed air, spraying upside down on brown connector(4,5,6) ICM. Guess what missfire went away for approx 30 seconds. then came back. I can notice the temp. difference between (4,5,6) ICM and (1,2,3) ICM. I also noticed that when sprayed the (1,2,3) ICM stayed colder/wetter longer. Probably running cooler. Now, I'm gonna switch ICM positions and give another go. Laptop needed to get charged back up.

On the VCDS use with 2008 VW , I used it do the DSG trans drain and refill on her car. I wasn't able to read all the blocks but at least it read the trans temp so I could correctly fill and get to correct level.