2005 Equinox Stumbles on start up

[Midlife Cruiser]

2005 Equinox runs rough immediately after start up. If I put it in gear right after start up and try to back out of the garage it almost dies. If I rev the rpm right after start up it revs to about 3000 & then stays there for 5 to 7 seconds like the throttle is stuck and then slowly returns to normal idle speed. After about a minute of warm up it runs fine. It's not showing any idiot lights on the dash.

[danielsatur]

1) New air filter
2) Clean MAF sensor with CRC electronic cleaner.
3) Clean throttle body.

[Midlife Cruiser]

I just blew the air filter out & cleaned the throttle body. No change. Do I just spray electronic cleaner on the MAF sensors or do I need to wipe them off?

[Tech II]

Is this a TAC system, or does it have an IAC?

[Midlife Cruiser]

Sorry...over my head "TAC or IAC"?

[Midlife Cruiser]

Is that Idle Air Control/Throttle Air Control? How do I tell?

[Midlife Cruiser]

Ahhh...Thermostatic Air Cleaner. The air cleaner has a removable element and the top half of the housing has an element that is fixed in place. The MAF seems to be between the air cleaner housing and the throttle body.

[danielsatur]

Also do a Google ''Youtube DIY Auto clean MAF''

Some Incoming Air Temp (IAT) sensors are located on The MAF sensor & some are located on the incoming air duct work.

Both need to be clean, so when the air is metered cold, the ECU/PCU can trigger a longer fuel pulse. kinda, sort of like a choking effect on a carb.

[Tech II]

Older systems used an Idle Air Control solenoid, to control slight changes in air flow for idle and loads......also the throttle plate is controlled by a cable....

TAC systems(Throttle Actuator Control) have a motor in place of a cable, controlling throttle plate opening......and don't use an IAC valve......

TAC system......clean throttle plate and mating bore as best as possible......then with key out of ignition, disconnect the neg bat cable, and then the positive one....hold cables together for a minute.....this resets all modules......also makes sure the tube that goes from snorkle to the rear valve cover is intact.....

For cable throttle bodies, once again clean the throttle plate AND the mating bore.....also remove the IAC valve, clean the pintle and the mating passage......

Check for any possible vac leaks.....once again check the fresh air tube to make sure it is attached to the rear valve cover....

[danielsatur]

After normal operating Temp, does the RPM's stay the same with Air cond on high max & off ?

Is this just a Cold hard start problem?

[Midlife Cruiser]

Yup, once it's warmed up the idle is stable with A/C on or off or on Max. It's just a problem at start up. Can't say it's only "cold start" problem but if it sits for more than a half hour or so it will do it again.

[Midlife Cruiser]

Sounds like I have several things to try. Thanks for all the info. I'll reply after I try them all. Could be a few days. Thanks Again!!

[danielsatur]

Symptoms of a bad cold hard start is usually a bad or dirty MAF sensor.

Good Luck!

The Incoming Air Control (IAC) is used to bump up the rpms under load without notice when the air cond is on, it sounds like it's doing the job.