Skip the auto shop - Our mechanics make house calls

Q: Muffler is loud and the van jumps when in idle. When it jumps the muffler makes a puffing noise and smells.

asked by on

Loud muffler. Van Jumps forward in idle and RPM goes up. When the van jumps, the muffler puffs simultaneously and smells.

My car has 150000 miles.
My car has an automatic transmission.

This may be related to a failing catalytic converter or potentially a dirty or failing idle air control valve. The idle air control valve reads the air intake as it enters the motor and relays this information to the computer which makes adjustments to fuel. When this is not working properly, you may experience an intermittent idle problem as you have experienced. This may also cause a rich fuel condition producing a smell of fuel as well.

To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your location to diagnose the smell and noise firsthand. One the issue has been pinpointed, the mechanic can service the catalytic converter or idle air control valve as necessary. Best of luck.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Muffler is loud and the van jumps when in idle. When it jumps the muffler makes a puffing noise and smells.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Is this a power steering problem?

It sounds like you may have a power steering leak, a failing pump or potentially a steering rack that may need to be replaced. When the power steering pump is low on fluid or damaged and needing to be replaced,...

Q: Engine power loss and odor from the exhaust

Hello. The symptoms you are experiencing can be caused by a wide variety of issues. It may be possible that the vehicle has suffered a component failure, perhaps at the fuel or ignition systems, which is setting off the light...

Q: Turn off consumers low battery

You will want to have the battery charged and load tested before replacing it. Since you have already replaced the alternator, the battery replacement is generally the cure for the "turn off consumer low battery" warning light. You may want...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...