Continued P0411 code and roughness
Greetings friendly Mafia members--
I'm having some ongoing issues with my ZHP and I'm wondering if anyone can provide a word to the wise.
It's been running a bit rough at idle. I've had a SES light (P0411) for a while now. My mechanic has had it several times--he's replaced the secondary airflow pump, the sensor and the switch. He's found no vacuum leaks or damaged hoses anywhere. Still the problem persists.
A little more recently, I was coming home, and the transmission light came on at a stop sign (steptronic). The car wouldn't go into first or second gear, even manually. It wasn't super cold out, I'd been driving the car for about an hour. I turned it off and waited 10 minutes, restarted and the problem persisted. I turned it off and left it alone for about an hour, and that seemed to solve the problem, it's been operating more or less normally ever since.
Well, mostly. It seems like now it tends to upshift when I take my foot off the gas sometimes..I feel it shift up at low speeds and the engine makes a bit of a strained, grinding noise. If I accelerate a little it downshifts again with a small thud feeling.
Not sure if this is related, but sometimes a particular light in my car (I notice when it's dark) tends to flicker erratically. It'll usually be the compass light on the mirror or the gear-selector light. It doesn't rhythmically flicker like a failing alternator..much more sporadic.
Related to the transmission, my mechanic suggested it could be a bad battery or possibly even the MAF sensor. I unplugged the MAF and the car ran rougher..not a whole lot, but I noticed it. I ordered a cheap one off eBay just to see if it made any improvement. The battery doesn't seem to be particularly old, however it is a weird, cheap little battery that looks like it came from a roadside service (AutoZone brand). The previous owner had it put in.
Any idea how I could pin down the P0411 code (or transmission/flickering lights issue)?
