Very good question....I received an email yesterday from a fellow A4.org member, and he did pose that question to Wett. Here's what he wrote to me:<p>-----Begin Included Message------<br>I saw your A4.ORG post regarding Wett "Stage Two". What caught my eye was your interest in a cat back exhaust. I'm thinking the same, so I called Wett to find out if it would have any negative consequences on my chip's performance. To my surprise, they claim some people have actually LOST power after the exhaust installation. I have emailed Frank Wetterauer<br>directly to try to get a better answer. Conventional wisdom is that turbocharged cars benefit from free flowing exhaust systems, and most chip manufacturers claim 8 - 10 more horsepower (i.e. TAP's 12.5 psi chip plus exhaust equals 200hp).<p>I'll let you know if I hear from Frank.<br>

On the way home tonight I had the following happen in my chipped 1.8t:<br>- just started engine<br>- driving 30 mph<br>- engine starts kicking like a timing error or missing cylinder<br>- engine light flashes for a few seconds<br>- engine light stays on continuously<br>- car runs fine (light still on)<br>I found 2 identical reports in the archives but neither indicated the resolution. Is there a known cause for this problem?<p>

just curious, which manufacturer are you chipped with?

The check engine light will flash when there is a condition that can cause catalytic convertor damage such a a misfire. This is part of the OBDII spec. Misfires can be caused by so many different things such as ignition problems, fuel problems, etc. If after cycling the ignition and the light stays off, I say drive it and see what happens. The system stores trouble codes which your dealer can retrieve and may give a clue as to what went wrong.

I'd prefer not to identify the chip unless the problem can be attributed to it. The chip is not socketed.

No my chips not socketed. A bad connection somewhere in the ECU sounds like a reasonable source of the problem though.<p>Thanks