Thursday of this week, my car started idling poorly. Not quite enough to stall, and it ran fine over 1,000 rpm. It just wouldn’t idle right.

My first thought was an intermittent misfire, meaning a coil pack or spark plug maybe. But this afternoon I got around to having a quick look at it. P0171 and P0174 codes, lean run condition. Hmm.

I took the airbox off, thinking, maybe a rodent ate a hole in the intake boot? Or the MAF sensor is borked, or the DISA valve is acting up. On an E46 those were the things on my “I’m going to look into this for 15 minutes” list.

Welp, sure enough, I pulled out the DISA valve, which changes the airflow in the intake manifold, and it’s quite broken. In particular, it’s not attached on the side that actuates the valve. So... a quick order of a replacement that will be here Tuesday, and I’m quite confident I found the issue.

If I hadn’t found anything broken here, I would for sure have given this a thorough cleaning. It’s quite nasty. But it’s not going back in anyway, so here’s a little show-and-tell. 

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I stuffed rags in the openings that are now just asking for rodents to make themselves at home before I replace that part next week, and I thanked the Car Gods that I have another car to drive between now and then. Then I opened a beer.

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Cheers to saving money with basic DIY skillz. Oh wait, the car’s going to the shop next week for a front end clunk that I don’t have time or space or tools to really properly deal with at home anyway, so... I’ll just have another beer then. Right.