Problems starting

My Alero runs great but I have problems starting my car when it is realy cold and when my car is warm. When it is cold I need to crank for a while and give it gas, when it starts is idles up really slow. When my car is warm I will crank it over, it starts right away, idles up and down and then stalls, if I rev it up a few times it will then idle fine. Any ideas?

My Alero runs great but I have problems starting my car when it is realy cold and when my car is warm. When it is cold I need to crank for a while and give it gas, when it starts is idles up really slow. When my car is warm I will crank it over, it starts right away, idles up and down and then stalls, if I rev it up a few times it will then idle fine. Any ideas?

Which engine do you have?

Which engine do you have?
3.4L 1999 Alero

3.4L 1999 Alero

Check the electrical connection to the Intake Air Temperature sensor (IAT) located on the intake ducting and connection to the MAF sensor.

Also check connection to and clean the Idle Air Controller (IAC) located on the throttle body. The IAC will cause erratic idle and affect engine vacuum.

Check the electrical connection to the Intake Air Temperature sensor (IAT) located on the intake ducting and connection to the MAF sensor.

Also check connection to and clean the Idle Air Controller (IAC) located on the throttle body. The IAC will cause erratic idle and affect engine vacuum.

How do I check them?

What oct. are you using? when i use 93 oct, it does not happen much as the 94. I have the same prob, every great once in a while. this happens to me once every 6 months on one day only.

What oct. are you using? when i use 93 oct, it does not happen much as the 94. I have the same prob, every great once in a while. this happens to me once every 6 months on one day only.

I only use regular, but I will try it thanks.

If that does not work, Bob as well had a great idea.He is great with cars as well.Hopefully its the gas, not anything else, but you know how cars can be! lol

How do I check them?

Try Andrew's (Vamc) suggestion and make sure you did not get bad fuel (moisture). Normally when these sensors act up they will trigger a SES light and store a DTC error code but not always. So you will have to manually troubleshoot. On the IAC valve it is at the top of the throttle body held on by two Torx screws. You can remove it and inspect the pintle for carbon and make sure it moves freely. The IAT sensor can be checked with a multimeter and ohmed out based on corresponding air temperature. It is a thermistor. On MAF you can remove the input rubber duct from the air filter. Try cleaning the screen and hot wire elements with electrical contact cleaner and let dry before re-installing.

If you get a SES light get it scanned for error codes.

Also check all vacuum lines on the intake manifold and throttle body. Make sure they are in proper place and tight. Good luck!

That as well is a great idea. You got to love all the sencrs.

That as well is a great idea. You got to love all the sencrs.
Would a leaking intake manifold gasket also cause this problems and if so how do I tell if the gasket is leaking?

Would a leaking intake manifold gasket also cause this problems and if so how do I tell if the gasket is leaking?

Possible. Check your engine oil and coolant for cross contamination. Also low coolant levels or high oil levels. An engine vacuum test can be performed to see the level of possible vacuum loss.

I've had the intake gaskets replaced and I am quite sure Andrew (Vamc) did too along with probably everyone else on the Alero forum.

Another sign is engine running hot and overheating.

Yeap, i had mine replased. Did not have a choice in the matter, but i have now 132,500mi on it, and it still runs great.

Well I checked my IAC sensor today and it OHMED out fine noticed alot of carbon build up, so I cleaned it and reset the Pintle to the right depth and my car is running much better, idles better and starts fine. Thanks for all the great advice.
My next step is to definetly replace that darn intake manifold gasket before I run into more problem.