Whether you’re trying to build up speed or overtake, the engine has to respond properly to the gas pedal input. Chevrolet trucks are reliable machines, but they’re not immune to problems, and loss of power is one of the more common problems.
Let’s take a look at the main causes, symptoms, and solutions to fix this issue. We’ll start with the most trivial issues before getting into the more serious failures.
How vehicles accelerate
To properly identify power issues, we need to review the basics of acceleration. The throttle pedal is directly linked to the intake manifold and controls the amount of air sucked into the engine. Fuel mixes with air and is ignited by a spark at the right moment to generate the most powerful explosion. Pistons work in rhythm, with some pushed down to rotate the crankshaft, and others going up to compress the fuel-air mixture.
The harder you press on the throttle, the more air will be directed towards the engine. The air-to-fuel amount remains the same per ignition, but now it’s happening at a much faster rate, spinning the crankshaft more times per minute, resulting in higher revs.
Running, and by extension, accelerating is the primary function of the engine and involves the entire system in its operation. This will make diagnosing the problem more challenging, but by observing the symptoms, you can rule most of the causes out.
Dirty Fuel & Air Filter
We’ve reviewed how the engine gets its power from air and fuel mixture. Before arriving at the engine block, both air and fuel are filtered through separate means.
Air filters are made out of natural or synthetic fibers and collect dust, sand, and other imperfections that would affect the ignition quality. Over time, the particles accumulate to such an extent that air can no longer pass through in the required volume. When you press on the gas pedal, the air-fuel mixture will be too rich in fuel, causing increased fuel consumption and a power limit.
The same principle applies to the fuel filter, which looks like a small, cylindrical air filter inside a see-through or metal case. See-through models are particularly handy as they allow you to inspect the condition of the filter at any time. Both filters are very inexpensive, easy to change, and require only basic tools.
A Chevy truck that has been sitting in the open for several months or even years becomes a fine shelter for critters, bugs, and rodents. Properly identifying a clogged exhaust is very difficult, because your focus will be entirely on the engine. Because this is a rare occurrence, once you’ve exhausted all other options, I advise disconnecting the exhaust manifold from the engine, and see if the power is restored.
The ever-increasing emission standards are forcing manufacturers to create new ways to reduce the output of their vehicles. As optimizing fuel economy can only go so far, the focus is placed on the exhaust system. Petrol particulate filters (PPF) are not prone to clogging up, due to higher running temperatures and lower complexity. Diesel systems are far more complicated, with DOC (diesel oxidation catalyst), SCR (selective catalyst reduction), and DPF (diesel particulate filter) working with other systems to reduce emissions to a minimum.
The best solution is preventive measures, but if your truck is already having problems, there are still things you can do without going to the mechanic. City and economic driving lead to the problem emerging, as particles accumulate in the system. The faster the engine runs, the hotter the exhaust system will get, burning off particles with heat.
Whenever there’s a long stretch of incline or highway, put the transmission into a lower gear and keep the engine running at roughly 3,000 rpm for 10-20 minutes. I would advise consulting with a mechanic, as trying to force a high volume of exhaust fumes through a seriously clogged system is not recommended. However, if the problem has just emerged, the heat solution is not only safe but also recommended over disassembly and cleaning.
Clogged Fuel Tank
Problems with older Chevy trucks can be related to an unclean fuel tank. Over the years, a large amount of fuel of varying quality goes through the fuel tank, and when combined with its natural predisposition to rust, the fuel delivery system will not be able to keep up with the engine’s needs. Instead of taking the vehicle to a mechanic, buy a boroscope camera. It will cost you less to take the truck to a mechanic, and you can find further you for it after checking the fuel tank.
Failing Fuel Pump
The fuel pump is responsible for transferring fuel from the tank to the engine, at the right pressure. As it has to run constantly to supply the engine with fuel, eventually it’s going to fail. The symptoms include noise coming from the fuel tank, loss of power, uneven accelerating and idling, surges of power, anything that can be caused by irregular fuel supply.
If the fuel pump needs to be replaced, take the truck to a mechanic. Even if you have plenty of experience, working with or around a large amount of highly flammable liquid is simply not worth the risk.
Spark Plugs & Ignition Coil
Rough idle, misfiring, higher fuel consumption, loss of power can all be attributed to failing spark plugs or ignition coil. You’ll be able to replace them in just a few minutes, and the only tool necessary is a spark plug key. Disconnect the truck from its battery, take off the coil on plugs (COP), and swap out the spark plugs. At this point, you can also swap out the ignition coils. Do not overtighten the new spark plugs – work slowly and you’ll know when the tension is at the appropriate level.
Once you’ve ruled out the rest, the causes that remain are serious and due to the complexity of the job, require a professional to replace them. Diesel turbochargers can get dirty which causes them to work at decreased capacity, or even shut down completely. By driving in higher revs, the turbo can be cleaned to an extent, but in more serious cases, a mechanic will have to disassemble and clean it.
ERG or exhaust gas recirculation valve is one of the systems used to lower emissions and can be responsible for loss of power. You can attempt to replace it yourself, but the job is better suited for a mechanic. The worst-case scenario is failing fuel injectors. They’re one of the most expensive components inside modern engines, so do not self-diagnose injector issues. In fact, you should go as far as asking a second opinion in the hope that anything else is at fault.
We hope you’ll be able to find the cause for the power loss in your Chevy truck and restore it to its full potential! If you’ve liked this guide, take a look at some of our other articles, and learn more about vehicle maintenance and repairs!