Why does my Chevy Silverado idle rough?
While there are a variety of reasons your Chevrolet Silverado 1500 has a rough idle, the most common 3 are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
How do you adjust TBI idle?
Unplug the IAC valve located on the passenger side, rear of the throttle body. Start the engine. Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM.
What would cause TBI to run rich?
The TBI system is programed to run richer when the engine is cold. Your ECM might think your engine is cold and making it run rich (it’s like the choke on a carb).
What are symptoms of bad IAC?
Most Common Idle Air Control Valve Issues
- Clogged. Due to the flow of air in and out of the idle air control valve, it’s possible for contaminants to enter the valve chamber.
- Failing.
- Trouble Starting.
- Poor/Rough Idling.
- Car Starts, Then Dies.
- Backfiring.
How can I get more power out of my 5.7 TBI?
How to Get More Horsepower for the 1994 GMC 5.7 Liter TBI
- Fill up your vehicle with high octane fuel rated above 90 octane.
- Add fuel injector or carburetor cleaner to your vehicle’s gas tank every 3,000 miles.
- Install a cold air intake on your vehicle’s air intake manifold.
What should the idle speed be on a GM TBI?
Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Turn off the engine and disconnect the negative battery terminal from the battery using a wrench.
Why does my 1993 Chevy TBI stall at idle?
Timing is steady and not jumping all over. It is a fuel issue. The only code that ever sets is a P044, lean exhaust, and the exhaust is really lean. We have swapped PCM/PROM with a same year Suburban, no change. Both vehicles run the same as this did using the other’s PCM.
What makes a 91 Chevy surging at idle?
My father in law’s ’91 Chevy was running poorly, so we put new plugs, wires, cap and rotor on it, and it’s running better, but it it still surging at idle. It basically almost dies out, and then surges back to life (probably a little higher than normal idle), then repeats continuously until you apply some throttle.
Why is my Chevy Silverado running rough at idle?
Really, your Silverado will be running rougher at any RPM, but a misfire will be most pronounced at idle. Spark Plug Wires – While not every model and engine combination of vehicles today comes with spark plug wires (a lot are now coil on plug), if your Silverado happens to have them, they can go bad and cause a rough idle.