I had a slightly high idle and a lean condition at freeway cruise.
I don't drive the car often these days (had a promotion from senior engineer to engineering manager in October, picked up another project car and then moved, I try not to keep things boring I guess?), but noticed when I drove it over the summer that there was something not quite right about freeway driving. I had taken a number of short trips that didn't really exercise it, but convinced myself on the yearly Laguna Seca trip that something was not right.
Hooked up my wideband and verified when driving the car from my old house to the new house that cruise AFRs where mid 17s or worse. So this morning I finally got around to popping the air cleaner off to back the APT out a bit.
Well, turned out that one of the shops that had worked on the car had attached the air cleaner thermal switch vacuum hose to the unused port for the hot air choke on my M4MC(now M4ME), the one behind the secondaries. What did they do with the little nipple next to the power brake booster attachment on the throttle body? Left it wide open.
I trusted them with a couple jobs back in April because I had once again scheduled myself into a corner... d'oh.
Oh well. To think I would have been that much happier over the summer if I'd simply lifted the air cleaner off.
I spotted the problem instantly...
For what it's worth, I'd taken the car in to have some exhaust flanges added so that I could drop the mid section (from headers to just in front of the axle) when working on it, and fix some broken flanges in the back from a trans swap I'd done back in 2012. They found a leak in the intake and I told them to go ahead and repair it as I was intending on having the car dynoed and didn't have the time to fix it. They ended up doing one more job after that... car slipped well into May and I missed the dyno date. May have been early June when I got it back.
