Hi all,
I've had a rough month with the old boy. Got what I thought was a bad tank of gas. Lost power, felt like misfires, the works. Babied it, topped off with different 93 gas, and put some water remover in it. Ran better, but idle awful. Swapped out idle air solenoid and cleaned the throttle body. That seemed to help. but then the issues came back in force a few weeks later.

Symptoms:
When under any electrical load: lights, high speed fan, A/C (which also kicks on the high speed fan), flashers, the idle dips really low, feeling like a stall.
Stalled a few times when idle was rough and I was turning (extra engine load from power steering)-- but main culprit seems to be electrical.
Definitely worse when you hear the fan click on.
Always better when I click the A/C off.
Never a problem at higher RPMs
Car runs great other than this idle problem.

Things I've checked:
Battery seems okay at 12.4 Volts. Always starts the car.
When running, it's putting out around 14V on the rail.
When stumbling, the voltage drops to around 12 (going by OBD-II logger)
Swapped out IAC
Cleaned throttle body
Plenty of drive cycles to relearn the idle.
Wiring to the alternator looks good and the passenger side ground looks good as well.

So what's next? Alternator? Seems to make voltage and current just fine during normal driving, just not at idle with higher electrical loads. Anything else to check before the swap?

Thanks,
AC

 

Have the battery load tested at a auto parts store. Good battery should be 13.2V not 12.4V.

Techron fuel injector cleaner may help if voltage is not an issue.

Mitsuatb

 

I think I have the same issue, not solved yet. I checked my sparkplugs, its new but you might want to check yours. i've had fake ones crack/melt during spirited driving

 

I swapped the MAF on a hunch. I would also get these occasional weird load/MAF readings in Torque when I hadn't changed the throttle (just noticed this yesterday). Had the MAF overnighted. So didn't think it was related to the electrical idle problem. But . . .

Purring like a kitten now. Did a 10 minute idle with 5 minutes on heavy load to re-learn it (pulled battery to test it, it was good).

Headlights, defrost, A/C didn't sag the idle. Voltage dropped a little bit but you could see the alternator recover after a few seconds and back up above 14V. It seemed like the ECU was calling for more air flow but getting bad data and dumping fuel (could smell how rich it was running when the idle stumbled).

I'll do a few more drive cycles before I fully declare victory but so far looking good.

Thanks for feedback, guys!

 

@Alacris where'd you get you maf?

 

AutoZone, about $300. Not OEM, but I wasn't even sure this was going to be the fix. So far the BSE version seems to be working well. Certainly better than before. Gets a little rougher when hot, but I've only had 2 drive cycles so far (but is nowhere near stalling out now).

 

ok thanks. are they like shiny plastic or same as your old one? i think may try the cheaper remans on ebay

 

Looked identical. I was surprised.

 

I have an OE MAF I'd sell if you are interested. I pulled it off the car years ago but it has been hanging around.