Skip the auto shop - Our mechanics make house calls

Q: Car misses and has a rough idle - 2001 Saturn L100

asked by on

My car has been missing and has a rough idle. I changed the plugs and also put in some expensive dry gas x2. Even though this is a Saturn, I had purchased it at Kia dealership, so I went to them. They said I had installed the wrong plugs and they replaced with the correct ones. When I’m driving at highway speeds, the car still misses.

I took it to the Saturn dealer and they reported that they had found the problem to be the ignition coil and performed the repair. The missing problem seems to be solved; however, my car still rough idles. What can I do to solve this rough idle?

A: Hello. There are several things that could ...

Hello. There are several things that could be causing your rough idle condition and therefore there are multiple possible solutions. Carbon buildup inside the intake manifold and valve train is a big cause of rough idle. This can usually be resolved by running a fuel system cleaner through your engine.

The wiring to the ignition coil could be damaged causing the rough idle you are experiencing. It is also possible that when the spark plugs were replaced, they were not gapped correctly which can also cause a rough idle.

I would recommend taking your vehicle back to the place that inspected the misfire issue and explain to them that you are still experiencing a rough idle and ask them to take a second look. You may be fortunate enough to have the issue resolved under warranty and at no cost to you. If you would rather have this looked at elsewhere, a certified professional from YourMechanic can come to your home or office to diagnose the rough idle and have this issue corrected.

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

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: Car is idling up and down while either parked or when driving.

Hi there. I believe O'reilly's sold you an IAC (idle air control valve) from the description you have given. OEM is the acronym for original equipment manufacturer. Seems odd that it was only fixed for a couple of hours. Sometimes...

Q: RPMs near zero

It seems like your car is experiencing a stalling issue. The engine will need to be checked for proper vacuum and idle control valve function as these are common faults for this type of problem. I recommend having a certified...

Q: Engine running rough and light now on.

Yes you could have bad fuel in the system if that is the case. However, you may want to check and make sure your fuel filter is good, and make sure there are no extra leaks in the the air...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...