Topic: HELP: Low/Rough Idle Issues. Stalling. Startup Hesitation.

[thedude]

Hey guys, I've been experiencing this issue for a little while now. Whenever I clutch in coming up to a stop light or in a parking lot after driving for a while my rpm's will drop low enough to idle rough and threaten to stall. In two cases I actually have completely stalled out and had to turn my car back on. Additionally, my car seems to really struggle to start in any temps below 0, yesterday was -7 at the ski hill and it cranked about 5 times before very hesitantly starting - almost like a misfire. Also, on WOT acceleration I seem to get a bit of hesitation mid-accel before the engine seems to catch back up with itself and continue to power forward.

Car is a 2013 WRX hatch with roughly 55,000kms on the engine and 115,000 on the car. No code is thrown when this happens.

Originally this started happening in March after my Service D (spark plugs, etc.), but after I replaced the air filter ensuring the box was secure, cleaned the MAF and pulled the battery cables for a reset the low idle seemingly went away and gas milage improved. Well it has come back and is very frustrating and not very confidence inspiring.

I just bought a new Costco battery today since I've heard they are decent - please let me know otherwise. I'm hoping this might help?
I had my spark plugs replaced by VEX in March, so they are by no means old. Is it possible they need replacing already?

Does anybody have any experience with this type of issue? Advice would be greatly appreciated as I can't seem to figure it out.

(Admins, if this topic is in the wrong thread, please move it accordingly.)

[DaDuke99]

Your car misses our elevation.

[Player One]

Whenever I clutch in coming up to a stop light or in a parking lot after driving for a while my rpm's will drop low enough to idle rough and threaten to stall.
.
.
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Also, on WOT acceleration I seem to get a bit of hesitation mid-accel before the engine seems to catch back up with itself and continue to power forward.

Car is a 2013 WRX hatch

I experienced this a couple times last winter, most notably driving back from a dinner party in Canmore. I did nothing about it and it has yet to come back. Subbing hoping someone knows what's up since I have a feeling it'll come back when the weather gets colder here.

[VTAKLOL]

Clean your throttle body.

[RWDragoon]

So this problem only came after we replaced the spark plugs?

I'd be happy to inspect or warranty them if they are defective the next time you're in Calgary. We've never seen an issue with spark plugs that only happens in the cold though. Are you getting a specific cylinder misfire or any other codes?

[JJx]

Check your grounds, I've had mine cause issues

[nemohm]

Did you replace the battery?

Disconnect it again, connect,  start the engine and let it idle for 5 min.
The ECU will reset the throttle body...

[thedude]

So this problem only came after we replaced the spark plugs?

I'd be happy to inspect or warranty them if they are defective the next time you're in Calgary. We've never seen an issue with spark plugs that only happens in the cold though. Are you getting a specific cylinder misfire or any other codes?

Hey Ryan, thanks for reaching out. Originally yes. However, I figure it had something to do with the airbox since I noticed that it wasn't securely assembled - poor mileage, hesitation and whooshing on accel were the giveaways. After I figured this out and secured it, the problems seemingly diminished however, the low/rough idle when clutching in to traffic lights/parking lot maneuvers, and hesitation mid-accel did not improve. Recently I've started to notice it's almost mimicking a misfire on the odd startup and requiring a few extra cranks - even more than the notorious Subaru multi-crank. When I was in for the March service, my Battery Load Test read 10 Volts @ 200 Amps as per my shop assist printout - hence me thinking this could be battery related. Anyways, I appreciate the offer Ryan, hopefully I can get to the bottom of it here.

Did you replace the battery?

Disconnect it again, connect,  start the engine and let it idle for 5 min.
The ECU will reset the throttle body...

I have not replaced the battery yet, I will update with any changes once I have done this.

Clean your throttle body.

I'm planning to this weekend. I'll install the new battery & reset the idle at the same time.

[ButterBear]

Im not the most knowledgeable working under the hood of a vehicle, but I've experienced "rpm's will drop low enough to idle rough and threaten to stall. In two cases I actually have completely stalled out and had to turn my car back on" due to a vacuum leak, in my case was loose connection of the recirculating hose on the BPV after removing my intercooler.