Skip the auto shop - Our mechanics make house calls

Q: rough idle

asked by on

it doesnt want to idle when its first started when the motor is cold, then after it warms up it will idle it will idle but a rough idle and when im sitting still its loping, like its getting to much gas and i also smell gas. i have already changed the spark plugs and spark plug wires and the filter is good.
My car has an automatic transmission.

These engines had a bad problem of getting excessive carbon build up on the valves that causes this problem. You may need to have the intake system cleaned out more than once using a combustion chamber cleaner. Be sure to clean the fuel injectors as well. Once this is done, the fuel pressure should be checked to make sure it is correct and not leaking. If it is, then it may be a defective pressure regulator. I’d suggest getting some assistance with this by having a certified technician, such as one from Yourmechanic, to help diagnose your rough idle and fix it accordingly.

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!

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: Why would a truck crank but not start until a plug wire is removed?

The engine may have a shorted spark plug that is shorting the coil out. I would recommend replacing the spark plugs first then replace the coil pack if it continues to not start. If you need help with this, a...

Q: 06 Ford 500

The engine should be scoped to evaluate the secondary firing patterns. That will provide an important clue. Apart from mechanical possibilities such as a blocked exhaust and/or loss of compression, what you are describing is due to an ignition, fuel...

Q: The power train notification is turned on and I had to get my car towed.

Hello. Thank you for writing in. There are a number of reasons the powertrain warning light would illuminate. This light covers anything related to the engine controls, transmission, and ABS system. The only way to know what exactly is triggering...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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 Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...