# 02 Passat Wagon 4cyl.T1.8

**URL:** <https://community.cartalk.com/t/02-passat-wagon-4cyl-t1-8/31541>\
**Category:** Maintenance/Repairs\
**Created:** [June 7, 2009, 5:18pm UTC](https://community.cartalk.com/t/02-passat-wagon-4cyl-t1-8/31541 "2009-06-07T17:18:55Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sherocks826](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@sherocks826](https://community.cartalk.com/u/sherocks826)\
**Post date:** [June 7, 2009, 5:18pm UTC](https://community.cartalk.com/t/02-passat-wagon-4cyl-t1-8/31541/1 "2009-06-07T17:18:55Z")

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I just purchased a used 02 passat wagon with complete care records, total miles: 189700. I put 85 octane in it, about 3/4 tank, and it ran fine for about 2 days. Yesterday, my MIL light came on and then starting flashing after a while. The light is always on, and flashes occasionally, especially upon acceleration. The car chugs and at times idels rough. (at about 3 gallons left in the tank of 85, I filled it with 91, and added octance booster). I ran it for 50 miles and still having symptoms. AutoZone ran the codes and they are P0301:cyl 1 misfire and 90420:catalyst system efficiency below threshold, bank 1. Do you really think it is my cat.convert.? Is the misfire enough to be drowning my catconvert? I have obviously been reading forums and such! 🙂 I put 85 in my turbo VW for crying out loud.

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**Author:** ![mrbean](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@mrbean](https://community.cartalk.com/u/mrbean)\
**Post date:** [June 7, 2009, 6:13pm UTC](https://community.cartalk.com/t/02-passat-wagon-4cyl-t1-8/31541/2 "2009-06-07T18:13:14Z")

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I’m willing to bet you have a bad ignition coil.  
switch the coils between cyls 1 and 2, clear the codes and see what new codes appear (back at autozone). If the new code is for cyl #2 misfire, then you know that coil is the culprit. They’re inexpensive if you search around online.

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**Author:** ![sherocks826](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@sherocks826](https://community.cartalk.com/u/sherocks826)\
**Post date:** [June 8, 2009, 5:19am UTC](https://community.cartalk.com/t/02-passat-wagon-4cyl-t1-8/31541/3 "2009-06-08T05:19:58Z")

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Thank you so much for the reply, that’s a good way to trouble shoot. I appreciate your time.