Page updated on 04-23-2018

03 Silverado idles very low and stalls

02-21-2006, 10:20 PM
I have a 2003 Silverado 4.8 V8 with 40,000 miles. Recently it has been idleing very low, around 300-400 RPMs. I'm not sure what the normal idle is. When I start it in the AM, It idles at about 1000 RPM, but as soon as I put it in drive the idle will drop to 400. In the morning I sit in a lot of stop and go traffic, so I am constantly on the gas and then coasting. When coasting the RPM will drop to 300 RPM and the battery amps will fall as well until it finally stalls. It is not consistent at all. I have let the truck warm up for about 15 min before driving and it still does the same. I read a few things here about cleaning the IAC valve, but I do not know how my throttle is controlled. I have had an autoparts store check the electrical system in case that was the cause, but they said that everything was fine. There is no check engine light on. This is getting very annoying since it happens up to 10 times during the commute. Any help would be greatly appreciated. Thanks in advance.


02-21-2006, 10:26 PM
Sounds close to my Wife's TB issue...

02-22-2006, 10:12 AM
Sounds close to my Wife's TB issue...
I remember posting in that thread, what was ever resolved, there was no follow up?

02-22-2006, 10:21 AM
I have an 01' with the 5.3 and it idles at about 800rpm... My 87 S10 has an idle problem and tends to stall and the timing is off on it. May want to have that checked out.

02-22-2006, 12:46 PM
I remember posting in that thread, what was ever resolved, there was no follow up?

Since I bought a new truck and don't drive hers anymore... outa' sight outa' mind :wink:

I still needa' get that fixed :grinyes:

02-22-2006, 12:55 PM
Thought that I would put my 2 cents in. I have had this problem with a couple of different vehicles, and in both it was the Idle Air Control Valve/Solenoid. On a Nissan Sentra, I took it off and cleaned it. On a Jeep Cherokee, I opted to replace it, since it was pretty cheap. This seems to be a common problem caused by carbon deposits that build up on the device. Anyway, it is definitely something to check.

02-23-2006, 07:41 AM
I had a similar problem and it turned out to be a dirty throttle body. Relativley easy to clean. Takes about 15 minutes.

02-23-2006, 11:21 PM
Thank you for the quick responses everybody. I have looked into it being the IAC, but I do not believe that the 2003 4.8 V8 has one. I bought a Haynes manual and the picture they show is different than mine and I cannot see any parts that resemble what it looks like. I have also searched for the IAC part on several auto parts stores and they always show that it is not available. Am I missing something, or do they use something else. If anyone can verify for me that it does have a IAC and where it is located, this would be greatly appreciated. Again, thank you all for your comments.

02-25-2006, 01:14 PM
Can anyone tell me if there is an idle air control valve on a 2003 silverado. Thanks.


04-27-2006, 11:08 PM
I just wanted to follow up and let everyone know that cleaning the throttle body fixed the problem. Thank you everyone for all of the advice. I had been dealing with the issue for months because I thought it was going to involve a hefty repair bill.

Thanks again:grinyes::grinyes::grinyes::grinyes::grinyes: :grinyes::grinyes::grinyes::grinyes::grinyes::grin yes::grinyes::grinyes:

06-29-2006, 11:56 AM
I have a 2003 Chevrolet 2500 HD and had the same problem; low, rough idle and stalling. Cleaning the throttle body fixed the problem. Thanks Faze3.

06-29-2006, 07:23 PM
My truck has idled at 500rpm's since day one. No problems.

09-08-2006, 08:06 PM
03 silverado stalls out at low idle, read that cleaning throttle body has worked for others. Did cleaning require removal and what type of cleaner

09-11-2006, 12:40 PM
03 silverado stalls out at low idle, read that cleaning throttle body has worked for others. Did cleaning require removal and what type of cleaner

No removal required. All you have to do is to remove the air intake assembly from the front of the throttle body and get a can of throttle body cleaner. I just did this on Saturday. I also removed the IAC and cleaned it with CNC electrical cleaner. It's a straight forward job.


09-11-2006, 09:04 PM
You could take an ohm meter and unplug the throttle position sensor and check the ohms as your wife gently presses the acelerator down. If they jump rapidly or are erratic I would replace it.Cleaning the idle control is a good idea. I have taken the plastic handle of a screwdriver and tapped the mass air flow sensor. If it is bad it will make a big difference.
My 5.3L acted like the accelerator was stucking in the morning or anytime on a cold start. I took the unit off and used carb cleaner steel wool and an old toothbrush to get it working properly. It took me about an hour to get it clean.

Add your comment to this topic!