Q: 1990 Volvo 740 idles roughly

asked by on August 17, 2016

The car has a turbo engine. It has been idling very rough. The RPMs would erratically increase and decrease. I had a new head gasket installed. I replaced the spark plugs with new ones as well as the spark plug wires, rotor and cap. It sometimes feels as if the car would stall. I had the vacuum lines checked as well. Do you have any suggestions?

Car idle is rough Inspection $94.99 - $114.99 Get a Quote

Hi there, thanks for writing in about your 1990 Volvo 740. The symptoms sound similar to a vehicle suffering from a boost leak or electronic air metering and fuel delivery faults. The vehicles do not have the new OBD-II ports, but our technicians are equipped with factory service instructions to retrieve trouble codes. Avoid an unsafe situation by continuing to drive. To have this resolved, consider having a certified mechanic, such as one from YourMechanic, inspect the rough idling problem in order to have this properly fixed.

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

What do the steering wheel radio controls do?
A quick look at the steering wheel in your car will show you there are quite a few different buttons available. They all provide you with a convenient way to interact with different systems in your car without having to...
Car dies
There could be quite a few things that can cause this. Reading out faults from the engine computer will be key to guiding the diagnosis in the right direction. Depending on when the stalling occurs -- at idle, part load,...
Car revved & lurched over curb while foot was on brake
Hello there, issues like this are very uncommon. When the vehicle does not stop like this it obviously makes the vehicle unsafe to drive and is a cause for concern. The most likely causes of this would be something obstructing...
How do I take a car out of storage after 30 years?
The best route to take is drain and refill all fluids, especially gasoline if any was left in the tank. The entire fuel system should be drained and fresh fuel added. Spark plugs should be replaced. Before removing them, it...
cylinder 2 misfire.
Engine misfires can be caused by many different things, but there are a few suspects that occur more than others. Generally, misfires are caused by either a spark or fuel issue or in cases, a combination of both. Spark related...
Check Engine Light is on
Your check engine light may come on for many different reasons such as a faulty mass air flow sensor, a faulty O2 sensor, a bad catalytic converter, bad spark plugs or wires and many other reasons. Unfortunately due to the...
Car is tapping
Occasionally, belt driven accessories are the source of noise so you can try to isolate all belt driven components by removing the serpentine belt and briefly run the engine. If the noise remains, a common source of tapping is the...
Is there a dogbone mount on the driver's side? There's one on the passenger side, but it seems fine 2001 Chevrolet Cavalier
Hi - no, there is only the one dogbone link up top. There are 2 motor/transmission mounts (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-engine-mount) where the engine/transmission are supported by the chassis, and these should be inspected for failure. They become soft, and fail with time,...
What happens if you put ow520 oil in a 2011 Chrysler 200?
Hi there- you will likely not notice any difference at all, and it is unlikely to cause any engine damage. The "0" (vs 5) rating has to do with the fluidity of the oil when it is coldest. It will...

Related articles

What Is the Purpose of Engine Gaskets?
Engine gaskets work as seals to maintain pressure, hold fluids, and prevent debris from entering the engine. Gaskets are vital for engine performance.
Symptoms of a Bad or Failing Timing Belt
Common signs include a ticking noise coming from the engine, an engine that won't turn over, engine misfires, and oil leaking in front of the motor.
How Long Does an Exhaust Manifold Gasket Last?
Your Your exhaust manifold requires a seal between the cylinder head and the exhaust manifold. This seal is called the exhaust manifold gasket, and is an incredibly hard-working part. The exhaust manifold is where all the engine cylinders’ burned gasses...