Why Does My Chevy Van Have No Power and Won’t Pull a Hill?

When an engine loses power, won't rev properly, and struggles to pull a hill, there are a lot of possible causes.

Fuel delivery, ignition, engine timing, airflow, sensors, or even the transmission can create symptoms that feel similar from the driver's seat.

That's why at MDC Automotive Repair, we don't start by choosing a part.

We start by proving what's wrong.

A 2014 Chevrolet Express 2500 with 202,163 miles came into our shop with a simple complaint:

The vehicle had lost power.

Verifying the Customer's Concern

The Check Engine Light was on, so we started with a road test.

There was no question about the complaint.

The van had very little power, would not rev properly, and could not pull a hill.

We scanned the Engine Control Module and retrieved several diagnostic trouble codes:

P0011, P0068, P0101, P0326 and P0420.

Multiple codes don't necessarily mean multiple failed parts.

They give us information about what the computer is seeing, but the codes themselves don't tell us which component to replace.

We needed to determine what was actually causing the loss of power.

What Happens When an Engine Can't Exhale?

An engine is basically an air pump.

It has to get air in—and it has to get exhaust gases back out.

If the exhaust system becomes severely restricted, the engine can't move enough air to produce normal power. The harder you try to accelerate, the more noticeable the restriction becomes.

The symptoms can be dramatic.

That's what we suspected on this Chevrolet.

So we tested it.

A Simple Test Produced a Big Clue

We opened the exhaust on both sides and drove the van again.

The engine's power returned.

That was strong evidence that we were dealing with an exhaust restriction, but we didn't stop there.

We installed an exhaust backpressure gauge to measure the restriction and verify the diagnosis.

The backpressure test confirmed that the exhaust system was restricted. We could also hear loose debris rattling inside the exhaust system.

Now we had measurable evidence of the problem.

What We Found

After discussing the diagnosis with the customer, we provided the option of a factory or aftermarket catalytic-converter assembly.

The customer chose the aftermarket assembly.

When we removed the exhaust Y-pipe assembly, we found the physical cause of the restriction:

The Bank 1 catalytic converter had come apart internally. Material from the damaged converter had traveled downstream and plugged the three-way catalytic converter.

The engine wasn't struggling because it couldn't make power.

It couldn't get the exhaust out.

The Repair and Verification

We installed the replacement catalytic-converter/Y-pipe assembly with new seals and exhaust nuts.

Then we cleared the diagnostic trouble codes and road-tested the van again.

Power was restored.

The vehicle could accelerate normally again, and none of the diagnostic trouble codes returned during our verification testing.

The vehicle was operating as designed when it left MDC Automotive Repair.

The Lesson

A vehicle with severe loss of power doesn't automatically need an engine, transmission, fuel pump, mass-airflow sensor, or any other part simply because a trouble code points in that direction.

In this case:

The customer reported loss of power.
We duplicated the problem.
Opening the exhaust restored the power.
A backpressure gauge confirmed the restriction.
Disassembly revealed the failed catalytic converter.
After the repair, a road test verified that full power was restored.

That's diagnosis.

At MDC Automotive Repair, trouble codes help us decide where to investigate.

Testing tells us what actually failed.

We Don't Guess. We Diagnose.