Kizashi Club

About 6 weeks ago, my 2012 Kizashi SE (80k miles) began to do the following: I stop the car, typically at an intersection (light, sign, etc) and with my foot off the gas and on the brake (in automatic mode), the RPM dropped to 450-550, the car idle roughly and would frequently stall out. I found if I put the car in neutral at a stop and applied the gas, I could keep the RPMs up enough to keep it running. On the dash, there were no warning lights. It did not run rough while driving, though it would be sluggish to start after it stalled. I found that the "disable hill hold" message would appear when I put it neutral, left-footed the brake and gave it gas to keep the RPMs up. I noted that when I was stopped, in drive, foot on the brake and it didn't stall, the car would sometimes "pulse" like it was fighting the brake. I thought it might be bad gas, so I put a bottle of treatment in the tank. It was getting increasing unreliable over a few days, so I took it into the nearest Suzuki service location. They did the following: checked the codes (none at all), tested the gas (fine), changed the oil, tested the fuel injectors, O2 sensors, air filter, ignition coils, fuel pump, throttle body, and changed the transmission oil. It stopped acting up. Last week it started acting up again. I put a bottle of rizoil gas treatment in a full tank of 87 octane and let it idle in my driveway for about 30 minutes. Once around the block and it seemed to perk up a bit, but still ran a bit slow on the idle. It also didn't accelerate as quickly, kind of bogging down in low gears. Since the dealer had no definitive idea, I am reluctant to return there. My regular mechanic looked at it before the dealer and had no idea. I dug through the forum here and found nothing clear. Any ideas?

Advice from a non-mechanic: were the spark plugs changed at 60k to the correct ones? If not, I would replace those and see if that's the cause. Make sure you get the correct ones, NGK SILFR6A11.

This sounds similar to a failing/malfunctioning throttle position sensor (TPS), though it's odd that there's no code being thrown.

Have you also tried disconnecting the battery overnight? Sometimes that can reset issues when the ECM relearns its settings.

These symptoms sound similar to someone who had an issue with their throttle body in an automatic model. They cleaned it and the idle got better, if I recall correctly. Hopefully, someone with more details can chime in.

I was thinking throttle body as well. However it was mentioned as one the the things checked. It didn't say whether they cleaned it or not. A dirty throttle body is the most common cause of the dastardly stumble when coming to a stop but the symptoms listed here don't quite match up with that.

Also, you might try switching where you buy gas. One other thing, is it possible you've got something restricting air intake? I'd look from the intake above the radiator and follow it to the air box and then from the air box to the throttle body.

I appreciate the ideas, folks!

Update: I have done the following: disconnected the battery overnight (didn't work). Checked the transmission fluid level (according to the manual) and that was fine. No change in operation. I will check the air intake. The throttle position sensor seems likely at this point. Any other suggestions?

No issue with the air intake. It is more prone to stalling than previously. Once I drop into drive from neutral, it have to floor the pedal to get it going. Once it picks up to cruising speed (35ish) i can back off the pedal and drive normally. Until the next stop...

I'm guessing dirty MAF sensor or Throttle Position sensor.

Father in laws Ford 5.4 did the exact same thing. It turned out to be the idle air control module. I replaced it for about $20. I looked briefly to find the one for the Kizashi.

Found the connector
https://www.rockauto.com/en/catalog/suz ... ector,2589

This one says it's for the 2.4 but probably for a gran vitara or something. They probably don't use the same intake and or intake parts.
http://www.carparts.com/details/Replace ... lsrc=aw.ds

Perhaps remove the one on the car and clean it. Good luck.

I thought it might be the Idle Air Control module, too. I hunted online and could never find one available for sale. Even downloaded the Chilton's guide for the car and ultimately found there isn't one. It must be built into the throttle body...

Yesterday, I let the car run in park for nearly 45 minutes. Went back and forth in the driveway, and even though it was running low on the RPMs, it did not stall out. This morning, I drove it to work, and it ran fine. The RPMs stayed up, no hesitation when pulling out. Like nothing had even been wrong. Nearest I can figure is that I got a questionable tank of gas and finally ran the car enough (used a quarter tank) that the gas treatment kicked in. I will top the tank with a higher octane for a few cycles and stay away from the place I filled it last time.

I appreciate all the ideas and suggestions, and I hope it is something this simple. One thing I did discover is that my wife's 2010 Kizashi shares an engine with my 2012, so as long as hers is fine, I can swap out parts to test what is/isn't working, if she'll let me .

Thanks!