Engine Shuts off when stopping - idle speed 750 RPM

I have a 2007 Aveo with 20,000 miles on it.
Suddenly it just started stalling when stopping for traffic lights or stop signs, or just in heavy traffic.
Engine restarts OK but idles at 750 rpm instead of 1,000 rpm, which it has been doing since it was new until this problem started. As long as I feed gas to keep the rpm above 750 rpm, it doesn't stall.
Now the "service engine" light comes on.
Unfortunately, I did not buy the repair manual (Helm Inc) - first time in fourteen GM vehicles. Can't find any info anywhere about this problem (Manuals are on order now).
The car has been in the garage for four days, after an initial visit last week when they said it was fixed... guess they were just buying time that day. It's under warranty and they said they've now got the parts based on a service bulletin... about injector seats or something in that area.
It looks more like a pollution control problem (in the past the engine light is fixed by reseating the gas cap!).
Anyone ever hear of this condition?
Thanks.
Norm

Is the engine rough at all? I had a similar issue a few months back (although a different car all together) where a spark plug wasn't firing and caused a little engine roughness, especially at idle. RPMs dropped enough for the engine to die at a stop if I didn't give it a little gas.

The engine doesn't appear to be misfiring, at least not all the time. At first it didn't at all, but a day or two later it did sound rough when trying to accelerate from 750 RPM. From 1,000 or higher, it seemed to accelerate fine. Then the "check engine" light came on, and it was running a little rough at times when accelerating.
I took it to the dealer and they checked the fuel injectors and fixed a recall for relocating the fuel line and a fuse box. (This recall was issued before I bought the car so I didn't bother with it since they should have done it before delivery - Dec. 2006). Of course, that didn't fix anything, so they've had it all week and expect to have it ready Friday.
The said they replaced the valve seats? and then had to check the head according to the technical notice. I don't think this will fix it either.
Doesn't sound like the same problem you were having. I've never seen anything like it.
Thanks for the response.
Norm

vacume leak issues??? check all ur vacume lines and such. maybe there is sumtin obstructing the intake like water got in and i9ts freezin up in the resonator or sumtin. or could be loose wires.... also the motor should not normal idle at 1000 rpms, the normal idle is around 750 rpms. well if it only has around 20k miles then take it back as it should still be under warranty. or if u wanna know what the codes are go to auto zone and ask them to do a code check for ya.

A very tough diagnosis without any specific OBDII codes. I have seen on several occastions where stalling, idle and accelleration issues were caused by a failing fuel pump. These concerns gave no check engine light. 2007 Aveos are electronic throttle control (no cable, they are throttle by wire), but TBW issues usually light up the reduced engine power light and will default to fast idle only if they have problems. Vac leaks typically throw all sorts of lean codes or misfires. *FLASHING* CEL means misfire.

Joel

use your warranty dude---its good for 5 years.

Mikedudley17 seems to have the answer. I just got back from the dealer where the car has been for the past five days... and still counting.
The mechanic seemed to know what he was talking about and said the engine check code (which I promptly forgot, 307 or something) indicated an exhaust leak and he had a technical notice (or whatever they call those bulletins).
He replaced a value seat, I couldn't see it. But the delay was getting the engine head checked for tolerances... outside machine shop job.
I was thinking the problem was in the pollution controls area and told the mechanic I had reservations about his fix. He said he was confident this would fix the problem.
About idle speed; I told the "advisor" I wouldn't take the car back if the idle speed was not at 1,000 RPM. I can't find anything that tells me what the idle speed should be (I ordered the repair manual(s) for $150 and hope it will tell me). Maybe you convinced me 750 rpm is OK, but I've never seen it that low for the first 20,000 miles.
Everything is under warranty, but tearing an engine apart this early creates a lot of doubts for me. I thought the AVEO had been around long enough that it didn't have any serious problems - big surprise!
Anyway, thanks for the input Mikedudley17 - I'm almost convinced they will fix the problem now!
Norm

OK mikeodonnell123!
I knew it was under warranty and took the car in but they pissed around fixing an old recall (had nothing to do with the problem) and checked the fuel injectors (also didn't seem to be that type of problem). Their work had no affect on the problem.
I took it back the following workday - I posted my question about this because the "advisor" between me and the mechanic was pretty vague about a solution. I always like to have some idea about what's going on... some mechanics are poor diagnosticians!
Thanks for the input. I plan to post the bulletin number and engine code when it's fixed just in case someone else has this problem.
Norm

Monday last week I took my 2007 Aveo (20,000 miles) to the dealer; got it back today - 8 workings days plus the weekend. I thought I'd add comments on what they did:
Paperwork shows Service Engine light flashing, stalls when braking, always idled at 1,000 RPM but now idles at 750 RPM and runs rough and stalls.
Referred to TECH: 443, scanned DTC P0300 miss fire on #2 cylinder.
Needs valve replaced as per TSB #2010397.
--RR head and replaced all 8 valves and seals.
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NHTSA #10017820 (03/01/2007).
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The dealer sublet the valve job and sent the head for whatever had to be done - that took four days plus the weekend.
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I reviewed the P0300 in the service manual but gave up - it pointed to lots of things but exhaust leak was always involved.
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Trivia: Over 15,000 of the miles on this car were highway driving, most of it on interstates at 70-75 MPH and some Texas state roads at 60-70 MPH.
Maybe four-cylinder cars aren't really made for this type of driving... or I just got a bad engine!
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Thanks for the responses... I'm not sure what I'm going to bitch about to Chevrolet's complaint forum. Ten days is a long time to fix a known problem: good thing I'm retired and didn't have to go anywhere!
Norm

i wanna add that if u were idling at 1000rpm after warm up there is def. sumtin wrong with ur car. u said that was normal tho??? my aveo at closed loop runs between 800-830 rpm.

If it was an older vehicle, I'd probably say that the EGR valve needs preplacing. At least that was a common issue back in the 80's. I'm not even sure if they use EGR valves anymore. It could also be other things. Like a vacuum hose, or exhaust manifold seal, or even wrongly gapped spark plugs. Worst case scenario you're loosing compression in the engine. If that's the case, then even if they fix the engine, it'll be a thorn in your side until the engine is completely rebuilt, or replaced.

On older vehicles there was a screw to adjust the throttle. These days it's controled by the computer based on sensors. You can actually buy different chips for different characteristics for some(horse power or fuel economy). I went shopping for sensors back when I had a cavalier, circa late '80s. And I took a volt meter with me. According to the book it was supposed to be between a certain range. Both of the replacement parts at autozone I tried exceeded that range. But I got the one closer to the books specified range since the one in it was higher. Not that it fixed the problem I had at the time (bad ECM / random excessively high RPMs).

I'll agree that some fairly competent techs, can't diagnose a car worth a darn. They can do a repair if you tell them what to repair. But don't expect them to know your car like you do. Or to know that the car wont start because it's out of gas. After they test drove it for over 30 miles.

Did you ever figure this one out?? I did a timing belt on my 2004 and it has been idling about 750 RPM ever since. I have a feeling that the crankshaft pulley is off by 1 tooth because everytime I rotated it the 2 turns as stated in the instructions, the crank pulley would be off a little bit. I think I need to set it back 1 tooth when I put it on the pulleys because when I took up the slack with the water pump, it would move slightly everytime. Other than the idling being off, it runs like it always has. I just concerned about burning a valve or something.

[QUOTE=toni1595]Did you ever figure this one out?? I did a timing belt on my 2004 and it has been idling about 750 RPM ever since. I have a feeling that the crankshaft pulley is off by 1 tooth because everytime I rotated it the 2 turns as stated in the instructions, the crank pulley would be off a little bit. I think I need to set it back 1 tooth when I put it on the pulleys because when I took up the slack with the water pump, it would move slightly everytime. Other than the idling being off, it runs like it always has. I just concerned about burning a valve or something.[/QUOTE

I have 35k on my 2005 Aveo which has always idled at 750rpm. If you had the valve timing off even 1 tooth you would have a noticable drop in HP. If it runs good you have done a good job.

IDLE 750 RPM TO 1000 OR 500 OR LIKE MINE 900 WHAT DO YOU DO WELL THERE IS A THING THAT IS CALLED A Throttle BodY AND ON YOUR CAR YOU HAVE 1.. NOW ON

AND I WULD TRY THE CLEANING. A BOTTLE IN THE TANK 94 GAS AND PULL OUT THE AIR FILTER AND THE SPARY IN THE HOLE 2 CANS OF SPARY OR SO IT WILL SMOKE. THATS OK TRY IT

i have spent a long time trying to fig u and get you some great thing but i just go in a loop

Just as an update, my problem cleared up after I reset the timing as it was off by about 1 tooth. In fact, I was getting 4 codes on my scanner. They all went away when the timing was correct. And the idle is right on now. Maybe the original posters AVEO jumped a tooth? Seems that the dealership would have checked that? Who knows?

Toni.

Thanks for letting us know what the problem was. Guess I was wrong about it running bad if the timing mark was off by one tooth. My Escort is like that. One tooth and it had no power. Did you replace the o ring on the water pump when you did your belt? I've heard that it will leak after retightening the tensioner on the new belt if a new o ring isn't put on. I'm wondering about that because I'm due to replace my belt. I would appreciate some information. Has anyone replaced the idler and tensioner pullies and the water pump at the same time? Do the camshaft sprockets have to come off to get the cover off the water pump. Can anyone steer me to a good online site for replacing the belt. I guess it would be too optimistic to hope for pictures. Thanks Guys. Dave

All I can say is that it worked for me. As far as the O ring, I just went ahead and changed out the water pump, I think it was only around $50, cheap insurance, where if you do lose it, it does a lot of damage so I'm told. They do recommend changing the idler and tensioner, however I didn't realize this until I was almost done and I didn't want to wait for the parts. as they weren't in stock. I wanted to replace the bearing in the idler, but it is molded into the pulley, no way to remove it without destroying it.
I don't know for sure about removing the cover to get the water pump off, like I said I had an All Data subscription ,but it ran out. I did print off some of the notes, I'll see if I can find them again. I did end up taking the rear timing cover off and I think it was needed to get the water pump out. If its just a straight belt change, its not that bad of a job.
I do remember resetting the timing though. I had my son hold the cam gear on the inside in position because it is up on one of the lobes and keeps trying to pop down off of it while you're trying to tighten the water pump bolts.
Here's a link to a site that I have found useful:http://www.daewootech.com/forum/viewtopic.php?t=10839. If found this and used it during my belt change, you can read my post and it may help you as well.
Good luck, Toni.

Thanks Toni for all the information. Fore warned is fore armed. I'm glad you say it is a straight belt change. I hate hard. I've done the timing belt on my Escort, but have yet to do it on the Aveo. I'll visit the site you have listed. Appreciate your help. Dave

I had same problem on my dodge grand caravan and was finally able to fix the problem by replacing the EGR valve.