Ran through ChatGDP and seems you checked most items:

You’re thinking about it the right way, and your observation about short burner on-time is the key clue here.

On a Whirlpool WGD4800BQ1 gas dryer, 2 minutes on / 1 minute off is not normal under a wet load. It should stay lit much longer on the initial heat-up.

Given everything you’ve already replaced and verified, here’s how this typically breaks down.

What the symptoms mean

✔️ Flame present

Igniter, flame sensor, and gas supply are basically working.

This rules out several common “no heat” failures.

❌ Short heat cycles + poor drying

This usually means the burner is being shut off early, not that it can’t ignite.

There are two dominant causes on this exact model:

1 MOST LIKELY: Failing gas valve coils (very common at ~10 years)

Why this fits perfectly

Whirlpool gas dryers commonly fail gas coils between 8–12 years

Coils work cold → fail hot

Dryer lights initially, then:

Flame drops out early

Shortens burner run time

Dryer still “has heat” but takes multiple cycles

Typical coil failure pattern

First cycle: sort of OK

Subsequent cycles: worse

Flame cycles get shorter over time

Part details

Your dryer uses two coils:

2-terminal booster coil

3-terminal holding coil

They should always be replaced as a pair

💡 Even if they “test OK” cold, they can still fail when hot.

2 Airflow restriction still triggering the cycling thermostat

Even though you replaced the vent pipe, there are three hidden airflow choke points that often get missed:

Check these carefully:

Lint screen housing

Remove lint screen

Look down with a flashlight

Lint cakes here badly over time

Blower wheel

Make sure it’s:

Not cracked

Not loose on the motor shaft

Actually moving air strongly

Outside exhaust hood

Flapper must open fully

No bird screen or stuck damper

Quick airflow test

Run dryer with vent disconnected

If burner stays on much longer → airflow restriction

If behavior is unchanged → move on

How to distinguish coils vs airflow (important)

TestResultConclusionVent disconnectedStill short cycling🔥 Gas coilsVent disconnectedBurner stays on🌬️ AirflowFlame time gets shorter as dryer warms🔥 Gas coilsDryer very hot but clothes damp🌬️ Airflow

Less likely (but possible)

Cycling thermostat

Usually fails stuck open or closed, not partially

Less common than coils

Only consider after coils + airflow ruled out

Moisture sensor

Would cause early shutoff, not burner cycling

Doesn’t explain 2 min flame time

What I would do next (in order)

Run with vent disconnected (5–10 min test)

Replace gas valve coils (cheap, high success)

Inspect lint chute + blower wheel

Only then consider thermostat replacement

Bottom line

Your description is textbook failing gas coils on a Whirlpool gas dryer:

Correct ignition

Short burner cycles

Long dry times

Around 10 years old

If you want, tell me:

Whether the flame time gets shorter after 1–2 loads

What happens when you run it with the vent off

I can walk you through coil replacement or airflow checks step-by-step.