Periodic choppy idle?

I've had my '09 LGT for about a week. I was out of town all week & left the battery on a trickle charger, because the car wouldn't start when I initially went to check out the car. The battery seems "OK", but the car doesn't necessarily start strong. I'm running it to see if the electrical system can sustain itself over the next few weeks. Seems to be alright for now.

 

Twice in the times that I've driven the car, after it's warmed up, the car has stalled with the clutch in. Both times, I think, I had just put the clutch in & was possibly turning the wheel. AC was on both times, probably.

 

The car idles between 700-800 rpm. If I'm sitting at a stop, every ten seconds or so, the idle will dip briefly. I hear it & see the shifter wobble, and then the tach dips & shoots back up (sometimes to 1500 rpm) as the engine catches itself.

 

I was used to this on my E46 M3, but it was more rhythmic with that car; few seconds up, few seconds down. This doesn't seem normal to me. Has anyone experienced this problem?

Possibly a iac going bad but it sounds like you may have a vacuum leak

That helps. If it continues, I'll bring it in for a look. Whoopie for the extended warranty.

Any chance that the battery died before these two times stalling? If the battery dies or is disconnected, the ecu will reset. This will cause an excessively low idle and people have had the car stall. I don't know if there's a correlation in your situation, but it's another thing to consider.

It's more than possible, it's pretty likely. What's the remedy for a reset ECU... seat time?

Turn the car back on when it stalls. It will go away pretty quick. I think my idle goes back to normal within 10 miles or so.

If this is the problem, then once you get your battery draining issue taken care of, it will go away.

Hmmmm... I've put more than 10 miles in since then. I'll likely have it looked at. At the very least, the dealer owes me a battery.

Update...

 

I brought it to the dealer & they told me I needed an idle relearn procedure, since the battery died. They did it ($45) and also found a nail in one of my tires ($35, DOH)... however, on the way home from picking up the car, it stalled again. I'm going to have to give them a call...

$45 for an "idle relearn procedure"? You got taken advantage of.

$45 for an "idle relearn procedure"? You got taken advantage of.

I told them not to rake me over the coals finding stuff, but I wanted a full inspection of the car... I didn't really care about cost, other than the tire. It's on the (non-Subaru) dealer I bought it from.

Same issue still exists. Five stalls coasting with the clutch in... one on the way home from the dealer on Saturday, two today, and a couple in between.

 

Dealer says a new panel filter (car has 26k miles) and a MAF cleaning should take care of it.

 

Fingers crossed. I'll know on Thursday evening.

Chances are very high you have a vacuum leak, and they don't want to spend the time to track it down. They'll keep throwing parts onto the car until they finally get down to that issue.

 

Regards,

 

Paul Hansen

http://www.avoturboworld.com

http://www.facebook.com/avoturboworld

They claim to have performed their 52-point inspection. My experience with this dealer is mixed. Nice guys, but I don't know about the quality of the techs. I've made it clear that I don't want to have to come back for this issue again, but who knows... I'm just tired of having to keep the revs up when I push in the clutch.

If they checked all the possible hoses there could be a vacuum leak out of, it'd be a 196 point inspection...

 

Regards,

 

Paul Hansen

http://www.avoturboworld.com

http://www.facebook.com/avoturboworld

Ha ha... I appreciate it. I'll emphasize that on Thursday. I really have no interest in having this persist...

Did they at least give you a reach around?

Did they at least give you a reach around?

Like I said... I don't care. I'm paying $35 for a tire repair--other than that, I TOLD them to go through the car with a fine-toothed comb & couldn't care less what the cost is. Evidently, though, the comb wasn't fine enough...

 

What's odd is that today the idle was perfect. Sat at 800 rpm at every light on the way in to work. When pushing in the clutch, revs would drop & stop at 800 every time, & stay solid. Intermittent problems are awesome.

 

I'd like to think that the idle condition has finally made its way into the ECU... but it shouldn't have taken 4 days and more than half a tank of gas.

had somethign similar on my car (not subaru) but it turned out to be a worn out radiator cap (Srs )

They tell me a vacuum leak would show up as a CEL... comments?

 

I told them I didn't want it back until it would idle consistently.

They tell me a vacuum leak would show up as a CEL... comments?

 

I told them I didn't want it back until it would idle consistently.

 

Wrong !

 

ask any of us that have had the line blow off the blue T. No cel. The car will pull hard but not CEL unless you leave your foot on the floor in 3rd gear.

 

Have them perform a vacuum leak test. if they don't know how, you stick a pint size paint can in the hose off the air filter box, pull the small vacuum hose off the blow off valve, give that hose a short blast of air from a compressor and put your thumb over the hose, listen for leaks.

 

Seems this is the second time I've typed this today.

 

 

Oh $35 to plug a tire...You can get a $3.00 plug kit from the auto parts store and fix it yourself. Use the other $32.00 to buy a small compressor from Harbor Fright.

This sounds like a vacuum leak to me as well. They can cause all sorts of problems in our cars.

^

 

my idler pulley is on its way out, not likely thats your problem, but it contributes to the same dip in idle and occasional issue starting.

Wrong !

ask any of us that have had the line blow off the blue T. No cel. The car will pull hard but not CEL unless you leave your foot on the floor in 3rd gear.

Have them perform a vacuum leak test. if they don't know how, you stick a pint size paint can in the hose off the air filter box, pull the small vacuum hose off the blow off valve, give that hose a short blast of air from a compressor and put your thumb over the hose, listen for leaks.

I've just gotten a call from them; they said that there's an aftermarket air filter that is completely deteriorated & they're getting a low output from the MAF. They're going to put in a filter, clean the MAF & TB, then take it for a drive & get new data.

 

Oh $35 to plug a tire...You can get a $3.00 plug kit from the auto parts store and fix it yourself. Use the other $32.00 to buy a small compressor from Harbor Fright.

I've had a decent compressor for >10 years. I plug my own motorcycle tires, so it's no mystery to me, but they patched from the inside (always preferable to a plug). $35 is worth the PITA for me.

 

my idler pulley is on its way out, not likely thats your problem, but it contributes to the same dip in idle and occasional issue starting.

No issues starting here. I've lost an idler wheel before (bearings)... you must be able to hear it starting to go.

Just picked up from the dealer... fresh filter & newly-cleaned TB & MAF sensor seems to have done the trick, knock on wood. It idles better, MPG seems to be a little better, and I can even lug the engine lower than what was comfortable before.

I had/have a similar problem I've had it there three times for the problem but they did fix the stalling; they said there was a stripped wire on the bolt what ever that means. But my car has a kinda rough idle and when my car kicks the fans into over drive it does the same thing as you I wish the dealership would stop giving me the run around and fix the dam problem already. When I took it to them they said well the engine is getting more load from the alternator which will cause it but I'm having a hard time believing that's how it supposed to run, I thought vacuum leak but I don't know where to begin to look .