Misfire and CEL on and off, please help me!

[boosted98tsi]

Ok i could really use some advice here. My 98 TSI is completely stock with about 118k on it. I've never had the timing belt done just in case that matters. The problem I have is that the CEL came on and the car started missing about a month ago. So I had it scanned. The guy said it was a misfire in cyl 1, and the coil pack was bad. So I went and got a coil pack off of a 96 TSI with about 40k on it. After replacing the coil pack on my car, I took it for a drive and th CEL came right back on and the miss returned. So I tried new plugs and wires but no help. So here is the weird part. I changed the oil and put in some fresh 20w50 and a new filter even though the oil in the car only had about 2k on it. I started the car and within 10 minutes, the CEL went off and the car ran great for about 2 weeks. Then the CEL and miss returned so I changed just the filter and again the CEL went off and the car ran fine but only for about 2 days. Does anyone have any ideas what could be wrong with my car? Thanks for any help!

 

[DSM_One]

I have the same problem though I haven't fixed mine yet. Most people here suggest to check the power transistor unit it might be that its the one that is actually bad and not the coil pack since the problem was not fixed when you changed it or it could be both. And at 118k I would strongly recommend changing that timing belt and do it as soon as you can.