Q: Car has been misfiring 2007 Mercury Mountaineer

asked by on January 11, 2017

I have replaced the spark plug a lot this last time my Mechanic said it was the manifold because the bolt kinda is by the cylinder replaced that half of the manifold so but it misfired this morning

My car has 122000 miles.
My car has an automatic transmission.

Engine is misfiring Inspection $79.99 - $89.99 Get a Quote

Hello - first task is to check for problem codes, whether the Check Engine is lit or not. If it is, there should be an indication of which cylinder is misfiring. Misfiring can be ignition related - plugs, coils, timing sensors, or fuel related - leaking or clogged injectors, or caused by air leaks. If no code, the problem may be random, and caused by air leaks in the intake manifold (your mechanic’s comments suggest that). I would recommend an engine misfiring inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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

What others are asking

4x4 light flashing but not engaging into 4 wheel drive

Hello there, many common faults will cause your 2007 Toyota Tundra to have the four wheel drive light flashing. The most common faults are a faulty four wheel drive switch, actuator failure, low transfer case fluid, or a shift cable...

Misfiring and emissions leak in 2000 Ford Crown Vic

It all depends on what you think of the vehicle. These Crown Victoria can run for an awfully long time, but you'd want to find out what this misfiring is to keep this car up and going. If the misfiring...

The car is misfiring and not picking speed

Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some cases, a combination of both. Spark related problems generally will result from things like ignition coils, crankshaft...

Stuttering with check engine light

If you are having an electrical system problem that is causing the lighting and other systems to have erratic issues then you need to check the alternator wire connections on the back of the alternator for loose or bad connections....

Overheating problem with my car.

Overheating is a serious problem that can result in extensive engine damage. It can also be caused by many different failures, from a faulty water pump to a blown head gasket. A qualified technician, such as the ones at YourMechanic,...

License plate light out

Sounds like you might be having an electrical issue. The circuit is simple as compared to other systems on your car, but a wiring schematic will still be necessary to trace the power distribution. There is a possibility that the...

Brakes hiss when I use them

Well, it sounds like you may have a vacuum leak coming from the brake booster. I definitely recommend you do not drive the vehicle until you have an independent mechanic look over it, as this is a major safety concern....

Vibration in steering wheel at 70 mph

Hello. If the tires that are currently on the car are defective, this type of vibration may occur. It may be necessary to replace them. Other possible causes for the vibration may be a faulty tie rod, rack and pinion,...

Service stable track light is on, service traction control lights on, rough idle. New throttle body.

Having symptoms such as this after having something like a throttle body replacement definitely suggests something went wrong with the installation, but not necessarily so. Coincidences happen every day in automotive. If I were working on this vehicle, I would...

Related articles

Mercury Certified Pre-Owned (CPO) Car Program
Drivers Drivers who are shopping around for a used Mercury vehicle may want to check out cars under their certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read on to...
Symptoms of a Bad or Failing Fuel Pump
Common signs include a whining noise, hard starting, engine performance issues, and an inability to start the car.
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.