What causes a GMC Sierra 1500 to have a lean idle?

Vacuum leaks can cause a lean condition and/or possibly a high idle. Check for cracked hoses a bad gasket or a faulty EGR or PCV Valve. 70 people found this helpful. The only other thing that will cause a lean condition is low fuel pressure. A vacuum leak will be problematic at idle and go away with higher rpms.

What are the symptoms of a bad idle control valve?

$0.00 1 Irregular idle speed One of the most common symptoms commonly associated with a problematic idle air control valve is irregular idle speed. 2 Check Engine Light comes on Another symptom of a potential issue with the idle control valve is an illuminated Check Engine Light. 3 Engine stalling

What causes the idle speed to go up or down?

The idle air control valve is programmed to regulate and maintain the engine idle speed at a constant rate. If the valve fails or has any issues it can cause the idle speed to be thrown off. This may result in an unusually high or low idle speed, or in some cases a surging idle speed that repeatedly climbs and falls. 2. Check Engine Light comes on

Why does my Chevy S-10 idle so bad?

Computer does show that it is in OPEN LOOP MODE and O2 Sensor shows RICH and while working the throttle and watching the code meter, the reading will move from RICH to LEAN and back to RICH again. While all of this has helped the engine somewhat, it still barely idles and it still lops really bad.

What happens when the idle control valve fails?

When the idle control valve fails it can cause all sorts of issues with the vehicle, and in some cases may even render it undrivable. Usually a bad or failing idle control valve will produce a few symptoms that can alert the driver of a potential issue. 1. Irregular idle speed

How can I check the idle air control?

To perform a rough check of the idle air control, remove the valve while reconnecting the wiring harness. While observing the valve with a flashlight, turn the key to the “ON” position, (DO NOT START ENGINE.) the valve should move slightly.

How to troubleshoot an automotive engine high idle?

The troubleshooting procedure for high and low idle conditions are similar, which are included in the following: Step 1 – If the check engine or service engine light soon has illuminated retrieving the diagnostic trouble codes could lead you in the right direction of what the problem is, or is related too.

What was the problem with my GMC pickup truck?

Specifically, the lawsuit claimed the active fuel management (AFM) system, piston rings and PVC system in these vehicles were faulty and caused excessive oil consumption, as well as premature spark plug degradation and engine malfunction.

When did the GMC Sierra have the most problems?

The model years with the most problems reported were 2004 and 2007, with more than 60 complaints each year, followed by 2002, 2003, 2005, and 2010, with more than 40 each year. Of the 112 problems, five different complaints have been reported 90 or more times.

How does the GMC Sierra heavy duty work?

Sierra Heavy Duty’s Gooseneck/ Fifth Wheel Prep Package eliminates the time-consuming aftermarket installation process entirely – and, more importantly, it was designed from square one to be strongly and seamlessly integrated into the Sierra Heavy Duty itself.

What do you need to know about the GMC?

With a complete portfolio of products, GMC Accessories has everything you need to personalize the interior and exterior of your GMC vehicle, as well as enhance its capability and performance.

Can a child sit in the back of a GMC Canyon?

Child safety restraints and car seats don’t always fit properly in the back seats of small extended-cab pickups, but a clever design engineered for the GMC Canyon may give families some newfound flexibility. Without a strong, durable pickup bed, a pickup truck is essentially nothing.

What should the idle rate be on a 1997 GMC Truck?

Underdog, I don’t know the 1997 5.7, but 1000rpm sounds like a high idle, not where it should “bottom out”. A V8 should idle at 500rpm. GoNDown, did you recently disconnect your battery? After I left mine dead in the yard for a while and didn’t charge it, when I started it up it ran like you describe for a few days and then it was fine.

What does low rpm mean on a GMC Truck?

Lower counts indicate that less air is commanded by the control module. This DTC is designed to detect low engine RPM that is not responding to increased IAC counts. AllOffTopic.com FTW!

What’s the idle RPM on my Chevy Suburban?

My 1997 Chevy Suburban (5.7) is acting up on me. When I start it up the RPM and idle seem fine. As I let it sit for a couple of seconds the RPM’s slowly begin to drop until they finally bottom out at about 1K. As soon as I put it into Reverse/Drive etc. the RPM’s drop below that mark and it struggles to stay running.

Why is my air conditioning not working on my GMC Sierra?

While there are a variety of reasons your GMC Sierra 1500 air conditioning won’t work, the most common 3 are a refrigerant leak, an electrical climate control issue, or a problem with the air conditioning compressor.

What happens when the diaphragm is ruptured on a GMC Sierra?

If the diaphragm has ruptured it will literally be like putting a hose with fuel into the intake and running it full. When it initially started to go it probably slowly flooded the engine to where it seemed to run ok but the excess fuel created a ton of carbon coating the O2 sensor. Since no air could pass through it, it gave a false lean reading.

What does the fuel smell like in a GMC Sierra 1500?

If so pull the air filter off and sniff the throttle body for a fuel smell. If the diaphragm has ruptured it will literally be like putting a hose with fuel into the intake and running it full.