Q: Violent surging from rough idle after cleaning throttle body and putting in gas

asked by on

The van has stalled 2x when stopped at a light, seems to coincide with letting my foot off the break. It starts again just fine. Also stalled when breaking in a parking lot and in a gas station. After cleaning throttle body and the iac valve, the van seemed to have a smoother idle. I noticed the van didn't have a throttle body cover or a gasket between the IAC motor and the intake passage. I placed a gasket b/w the IAC motor and the intake passage but still no gasket cover. Anyway, gas was on E. I put 1 gal. in the tank, the van sounded the same, and I noticed white emissions for the 1st time. Later, I filled the tank to 3/4 full, then stalled in the station. I then stalled at a stoplight. Later, in my driveway, with my foot on the break, the van's surges were the worst I've heard and felt. Each surge moved the van forward as if being pushed from behind while in park and in drive. I'm afraid to drive it. Any help is MUCH appreciated!!!

My car has 177000 miles.
My car has an automatic transmission.

Hello and thank you for contacting YourMechanic. You may want to perform a tune-up and change all of the spark plugs and wires first. Then check for vacuum leaks on the engine with a vacuum gauge. If the vacuum gauge reads less than 15 hg, then look for any vacuum hoses that may be disconnected or cracked.

A vacuum leak will stall out the engine and cause a rough idle. If you need assistance with finding a vacuum leak, then seek out a technician, such as one from YourMechanic, that can diagnose your rough idle and assist you with fixing your vehicle.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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. Violent surging from rough idle after cleaning throttle body and putting in gas

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: Occasional stalling and startup issues

Hello. This engine can stall for a number of reasons. If it happens only at idle, then it may have an intake manifold vacuum leak or a throttle body issue. If the throttle body is dirty, then this will occur....

Q: Gas tank's fuel pump stops pumping fuel randomly. Both fuel pumps are new, gas tank is clean, and a new fuel filters were installed.

Hello. The first thing to check when you have complete failure of the unit is the power supply. If the wiring going to the pump is loose or has a short somewhere, the power wont be delivered or will be...

Q: Hey when the car idles it revs up and down by like 300 revs or so and also when the car is off it doesn't recognize its in park.

The issue is the transmission position sensor is not working properly and registering that the transmission is in drive, neutral, or reverse. Check to see if the transmission is going into park when the shifter is in park. If the...

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 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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.