Rattling noise when engine lugging

My truck sometimes makes a rattling/ringing noise similar to shaking a tray full of screws when in low RPM (below 1500), usually when shifting 1st-->2nd speed. I rev the engine up to 2700-2800 RPM while in the 1st but by the time I shift into the 2nd, the RPM drops to below 1500 and I hear this awful noise.

Is this "as designed" on the Tacoma or could it be a defect?

 

Mine does that too when going up a hill and engine RPM are 1000rpms under load. I have an auto though.

 

I have a slight noise but not that bad. Is there any smoke? Does it sound like it's pinging? What type of fuel do you use?

 

No

What is "pinging"?

Regular

 

I have the same noise in my 6 speed normally in first gear at low rpms. I have read it could be a heat shield but I have not found the problem yet

 

What's a "heat shield" ?

 

There are heat shields under the truck where the exhaust runs

 

What Is Engine Pinging?
"Pinging" is the metallic rattling sound an engine can make when accelerating. It usually occurs when the vehicle pulls away from a stop and the engine is under a lot of load.

When an engine pings, it releases pollution into the environment in the form of nitrogen oxide (NOx) and raw, unburned hydrocarbons (HCs). These two chemicals are poisonous gases that show up as yellowish-brownish in a polluted sky. They can also cause respiratory problems like asthma and emphysema—a pinging engine is never a good thing.

Common Reasons for Engine Pinging
Improper Combustion Process
An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). In a properly-firing cylinder, the spark plug ignites the air/fuel mixture and a flame front starts on one side of the piston and burns across the top to the other side, which creates a rapid and evenly-expanding gas that pushes down on the top of the piston. When the air/fuel mixture is ignited prior to the spark plug firing, the two flame fronts collide, causing the pinging/knocking noise.

Engine Is Too Hot
An engine can ping because it is too hot. This is another uneven combustion scenario that is caused by the air-to-fuel mixture "lighting off" by itself. If the cooling systemdoes not keep the engine's combustion chamber temperature in check, the air-to-fuel mixture will begin to spontaneously explode. This is also called "pre-ignition."

Improper Gasoline Octane
In addition to cooling system problems, pinging can be caused by improper gasoline octane, an overly lean air-to-fuel mixture, or a lack of proper exhaust gas recirculation. The exhaust gas recirculation system (EGR) was created to neutralize engine pinging by adding a small amount of exhaust gas to the air-to-fuel mixture going in to the combustion process, which limits the peak combustion chamber temperature.

 

The noise sounds like it could be that reverberating, yes

 

So is pinging the same as knocking? Should the knock sensors trigger an engine code in that case?

 

Sorry for reviving dead thread but my third gen sometimes makes a quick noise when I start on a hill and don't give it enough gas. Sounds like valve clattEr on older Diesel engines when they crank and won't turn over quickly on cold starts.Not sure if this is harmful for the engine/drivetrain.