Ask Your Question

Angie's List Answers is the trusted spot to ask home improvement and health questions and get answers from service companies, health providers and consumers. For ratings and reviews on companies in your area, search Angie's List.

Top 30 Days Experts
Rank Leader Points*
1 kstreett 240
2 Guest_9020487 110
3 Guest_9190926 105
4 GoldenKid 100
5 ahowell 95
6 KnowledgeBase 95
7 skbloom 80
8 Guest_98024861 70
9 Guest_9311297 70
10 Guest_9400529 70

*Updates every 4 hours

Browse Projects By Category

Question DetailsAsked on 4/4/2017

Why does my car stall when turning or stopping at stop signs once in awhile?

i have a 2002 impala. So far Ive replaced exhaust system including cat. converter. map sensor o2 sensors air filter and its still stalling at stop signs once in awhile and cuts out when driving. What else could this possibly be?

Do you have the same question? Follow this Question

1 Answer

Voted Best Answer

I presume you are not getting a check engine light on this ?

First thing would be to see if it is throwing off codes - read the computer error codes, which many auto parts stores will do for free using their code reader, which plugs into the car computer, typically below the steering wheel. NOTE - do NOT let them do this with the car running or key on - some cars (I know Chryslers/Dodges and some others can have issues with this) can seriously screw up the computer settings and codes if you plug or unplug the code reader while the car is running, or even fry the computer if the connector shorts out the connection prongs. Stop engine first, plug in, start car, do readings, turn off, unplug.

I would also google for recalls or TSB's (Technical Service Bulletins, on known issues) for your exact year, make and model and engine. Recalls you can check at NHTSB or manufacturer website (at the latter, by vehicle VIN) - TSB's you have to google for a listing (some manufacturers do not post on their site - don't know if GM does). TSB's are for known issues for mechanics to look for, but that have not become a recall - but many times dealers are instructed by the manufacturer to handle it as a warranty or recall item if someone brings their car in and specifically points out the TSB on it. Sort of a stealth squeeky-wheel-get-the-grease under-the-radar recall. I have had a number of these, some like-safety items, which had not killed enough people to cause a forced recall but the manufacturer was fixing for free to avoid the issue getting to the Fed's attention.

Here is a link on the ignition switch issue several manufacturers have had - your year and model are included - so check if your car has an uncorrected recall on it for that -

Also - google this search phrase - 02 impala stalling. There are a number of blogs and articles, especially (or maybe only) with the 3.8L engine, on Mass Airflow Sensor or Crankshaft Position Sensor going bad, and also about moisture on the coil connections causing your exact symptoms. (The moisture thing, unless your engine upper end is all oiled up, should be easy to rule out if this happens in dry road conditions).

If runs well the rest of the time, then sounds like an intermittent thing - a sensor going bad, bad or loose connector at transmission or a sensor or at the computer, loose cable loom pulling at a connector, etc. Or could be fuel pump going bad. If only at low or high speed I would have said possibly plugged fuel filter or bad fuel pump, but if happening at both and running OK some of the time likely not a filter problem.

Could also be a faulty throttle positioner (problem we had twice on an 03 Dodge), fuel injector pump failure (if yours has a separate one), or (especially if doing it primarily at idle) a vacuum leak on a head gasket or a hose or PCV valve or such.

After code checking and checking for bad sensors, my next guesses (take a bit more work to do) would be to check the fuel pump pressure to be sure you are not getting low fuel pressure, then check intake manifold vacuum to see if there is a gasket/seal/hose leak intermittently letting excess air into the engine, causing it to die because it is running excessively lean. Also check battery voltage and charging voltage - some modern cars do very funny things when the battery is going dead and/or the alternator is not turning out the correct voltage. This can also cause the computer to throw off random bad codes.

Another common cause of this symptom - leaking vacuum hose or fitting at the power brake cylinder - moving around and letting air in, which leans out the mixture because the vacuum comes off the intake manifold. Eventually gets so bad car will not start when the crack or bad seal lets too much air in.

One other sometimes cause in some makes/models - gas cap not fully locked in place, so the emissions filter at the tank is getting incorrect airflow, which can act like a vapor lock on the fuel system. Rare, but a loose gas cap can do funny things - as well off sometimes throw off error codes that have nothing to do with the problem.

One other possible cause - don't know if Chevys are the same as Dodges, but on ours a defective timer module (which controls EVERYTHING that happens at an interval - from sensor checking to turn signals blinking to security system) started off by causing random lights going off and doors locking and unlocking by themselves, then eventually random very short-term engine dying or "staggering" mostly at idle (stops signs and such) but sometimes when driving too - eventually took out all lights and dash functions - on third one now because they keep replacing with same defective design. Final solution I found - because design resulted in overheating - keep the dash lights turned to full on because if at dimmer setting the light switch dimmed the dash lights with a resistor which overheated the adjacent timer module - problem solved.

I would also file a report with the NHTSB at link below because this is a critical failure - stalling at an intersection could cause an accident. If you file a report it will get more attention, and the manufacturer has to reply to it to the government - so they may offer to fix it for free. At least is enough reports get into the system for a given issue eventually it forces a recall.

Answered 3 years ago by LCD



This is James in Member Care. Thanks for your interest in Angie's List!

We'll be happy to help find top rated auto services, but it doesn't look like you have a subscription to the List yet. You can join by visiting or by giving us a call. Our call center is available 8:00 am-9:00 pm weekdays and 8:00-5:00 pm ET on Saturdays.

Thanks for your question and we look forward to assisting you!

Answered 3 years ago by Member Services

Related Questions

Terms Of Use
Privacy Policy