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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15133
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I was getting inconsistent idle. Sometimes racing, sometimes

Customer Question

I was getting inconsistent idle. Sometimes racing, sometimes low. I replaced the idle air control and the mass air sensor. Now it just races.
JA: Which particular sensor are you asking about? And have any trouble codes been triggered?
Customer: Yes mass air code and mis fire were triggered
JA: What is the model/year of your Chevy?
Customer: 2006 express 3500
JA: Are you fixing your Express yourself? What have you tried so far?
Customer: I replaced idle air control valve and mass air sensor
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 17 days ago.
Category: Chevy
Expert:  Chad Farhat replied 17 days ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 17 days ago.

hey how are you

1- have you checked for vaum leaks ?

2- did a smoke test or sprayed starting fluid around the intake & see if engine surges up ?

3- what are the fault codes ,check Engine light on?

4- where the parts new,u replaced idle air control valve gasket ?

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 17 days ago.
No vacuum leaks, new parts, new gasket. I had a friend run the codes. He said it was a mass air code and a misfire code.
Expert:  Chad Farhat replied 17 days ago.

get those fault numbers he came up with ?

fuel pump pressure checked,is it up to specs ?

and if you can fuel trim readings at idle ,long term & short term readings if possible , i can be more accurate for you on why ?

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 17 days ago.
I dont have any of that information
Expert:  Chad Farhat replied 17 days ago.

well can you get it ?

Expert:  Chad Farhat replied 17 days ago.

he needs to check the mass air flow sensor circuit & idle air control valve circuit , is he missing power or ground from pcm

could be pcm issue.

that will be my guess with out the info ii asked for that will most common issue but testing is needed i can not confirm that for you

Please let me know if you need anything else on it

Thank You

Chad Farhat

ASE Certified Technician