Skip the auto shop - Our mechanics make house calls

Q: Car sputters and has weak power after new spark plugs and ignition coil were recently replaced

asked by on

Several months back my car was experiencing sputtering, weak acceleration (in the lower gears) and poor power and undesirable fuel economy. So I replaced the spark plugs and this helped for a few months and then recently the issue cropped again so I replaced the ignition coil and this helped marginally, the sputtering isn't as bad but there's still a lack of power and good normal acceleration. I'm curious if there's another issue outside of the ignition and spark plug system that could be causing this symptom. Thanks!

My car has 200000 miles.
My car has a manual transmission.

There are actually several possible causes for the engine to sputter. It is possible for there to be a vacuum leak, a faulty oxygen sensor, a catalytic converter that is starting to show signs of failure, or even a possible problem in the fuel system. It will be necessary to do some further diagnostics to determine which system is causing the problem, and then figure out which part in that system is the root cause. For example, if it is found that there is low fuel pressure in the system, it will then be necessary to figure out if there is a weak fuel pump, clogged fuel filter, or something going on with an injector. If the problem appears to be with the ignition, there could be a problem with a spark plug, ignition coil, ignition control module, or a fault in the wiring. I understand you said that the plugs and coil had been replaced, but it is possible that one of them have failed again, since the problem is recurring. If this is something you could use a hand in identifying, I would suggest consulting a certified mechanic, like those available at YourMechanic.com.

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

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. Car sputters and has weak power after new spark plugs and ignition coil were recently replaced

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: Vehicle sputtering, hesitating and backfiring

When problems arise after a recent service, the best thing to do is go back and check all of the work. Mistakes do happen, and other parts can get bumped during a service. First, proper wire routing must be determined,...

Q: The Crankshaft Position Sensor broke at the block - how do i get it out? 1998 Chrysler Cirrus

Hello - I would soak it with penetrating oil (WD-40, PB Blaster, etc.) overnight, then try drilling the sensor for a screw/bolt extractor. If that fails, you may have to keep drilling with larger and larger bit sizes until, you...

Q: Car cannot start, engine unresponsive

The hard start issue on your 1994 Toyota Previa could be a variety of possibilities from something as simple as a dirty battery cable to a faulty starter, starter relay switch, or many other possibilities. Your vehicle requires a clean...

Related articles

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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.