Q: Car idles high and then low, and then becomes a 30 second cycle.

asked by on June 09, 2016

My 2008 Dodge Ram 1500 has a 4.7 L engine. When i drive and i stop at a light or i am just at idle, my truck idles around between 750-1000 and after a while idle goes down between 600-750 and it just becomes a 15-30 second cycle. what could cause this?

My car has 130000 miles.
My car has an automatic transmission.

Hello. A few things I would check are the throttle body, the idle air control valve, and the vacuum hoses. A dirty throttle body or idle air control valve can cause the idle to fluctuate. I would also examine the condition of all of the vacuum hoses, any cracked or leaking hoses can cause the idle to fluctuate as well. If you need assistance, a certified mobile mechanic from YourMechanic can inspect your vehicle’s idling issues at your home or office.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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

How do I turn off the flash lamps?

Flash lamps are a locking and unlocking feature. When you lock or unlock your vehicle with the remote keyless entry (RKE) transmitter, your turn signals flash on and off. This acts as visual confirmation, and can also help you see...

Gas pedal shakes when accelerating fast and misfire code came on?

Hello, thank you for writing in. The most common cause of engine or pedal shake (because you can feel the engine shake in the pedals) is a misfire. With that being said, its not uncommon to feel issues with brakes,...

My car will go into neutral while I am driving it. To get it to work again, I have to pull over, turn the car off, and restart a m

Hi there. Assuming you replaced the TCM (transmission control module) with a factory part, a transmission shift relearn procedure should have been performed. It could be that you have a TCM connector or wiring issue if the same code has...

Related articles

2011 Dodge Ram vs. 2011 Ford F-150: Which One Should I Buy?
Large trucks can be fun to drive, and even more fun to get dirty. Unfortunately, they may also cause you to get phone calls from friends who need to move into a new apartment. Fortunately, just having a truck may...
A Buyer’s Guide to the 2012 Dodge Challenger
The The 2012 Dodge Challenger has high performance, great features, and good pricing. It is comfortable for every day driving while still providing enough space for four people and their cargo. Key Features Under the hood of the vehicle is...
The Best Used Cars to Buy If You're a Farmer
If If you're a farmer, you know that what you need isn’t a used car – it’s a used pickup truck. How else are you going to haul around hay, implements, garden produce, fertilizer, and all the other things you...