- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
My Pontiac Grand Prix is also a 99, it has 216,+ thousand miles on it, it runs great, idles good, I need to replace the oxygen sensor tho as it shuts off on me while driving or sometimes coming to a stop. You might try checking the fuel filter and pump as well.
How does it idle when you first start or idle when hot.
On the top of the air intake tube there is a small screw which should when screwed in speed up the idle and if it dosent work or it idles fine when cold or warm at idle then its your GEARs are binding up and there's not to much you can do about that ........sorry
fuel shutoff switch is actually a fuel pump relay in the relay box under the hood, but it is not unusual for a fuel pump to work on and off before it finally dies. but it is a good idea to check the relay first.
try swapping it with the horn relay (if the horn works). pay attention to the direction the relay is in. on GM's, it's possible to put them in backward or even miss the connectors completely.
you also want to check for proper power and ground in the relay socket.
What is everything? does just the engine stops running, or does the heater fan and headlight stop too, does the the radio and parking lights stop working? does the starter engage after it stops? If you answer this question I will be able to help you.
check air flow duct where the throttle valve is . check the pvc valve . make sure it isnt stuck open. check the egr valve . it will stick open stall out motor .use a scanner it will tell you if you got egr valve problems. check fuel pressure. it could be stop up fuel filter bad fuel pump fuel pump relay.your car problem sound like a major vacuum leak . change spark plug and wires if they have not been change in a while. it could idle air control. hook a scanner .it could give you a code.