The reduced engine power will give fewer miles per gallon. But fuel economy may also be the result of other problems not related to the ignition coil at all. https://www.answers.com/Q/Does_a_bad_ignition_coil_effect_gas_mileage Read on to find out what most commonly causes a bad ignition coil: Wear and tear- All automobiles and automobile parts are subject to wear over time. Its the catalytic converters that suffer. The reduced engine power will give fewer miles per gallon. When the ignition coil malfunctions, the engine may crank but it will not start. 4. Misfiring is the most common symptom of bad Coil Packs. If you want to avoid ignition coil problems or other issues and save $100s of dollars that you’ll spend at the auto repair shop, you’ll need to service your vehicle often – you can use our mechanic-rated Auto Maintenance and Repair Manual to do this. An OBD2 scanner will give a more specific trouble code. Spark Plug gap will certainly effect fuel economy. Electronic ignition did away with points, and also reduced the need for timing adjustments. The gas mileage of your car is also going to have trouble. Unplug the ignition coil and remove the bolts or screws. For those who don’t, the likelihood of problems that cause the ignition coil to go bad is extremely high. Rough idling – Your car may run with a failing ignition coil for a short time. When you get to the “newer” stators (Primarily 2000 and newer in most models) a more common design contains 2 equally wound ignition coils that ohm out the same. The no-start condition can be more prevalent when the temperature is cold and the humidity is high. Malfunctioning ignition coils tend to overheat and cause breakage in the wire coils. Reconnect the wires according to the labels you put on them earlier. When I was driving around on the bad coil I was getting just slightly worse than normal gas mileage, perhaps 1-2 mpg less. Modern cars are loaded with electronics, including the ignition system. Most of the time bad mileage is caused by worn out plugs. A lot of our readers have the Auto Maintenance and Repair Manual printed on their garage wall and 92% of them haven’t visited the auto repair shop in the last year because they know what to do to avoid problems. A weak coil that has lost its ability to supply enough voltage to fire all of the spark plugs in a consistent manner can show itself in a rough or stumbling idle. Turn your car OFF and let it cool down completely. If you are not sure where the coil is located, check your owner’s manual, call the dealership, or do an Internet search. Just like the above two, poor fuel economy could be a result of a bad ignition coil. With a few tools, you can do it yourself. Whether it’s replacing the single coil mounted separate to the distributor, the HEI coil, a coil pack, or a coil over plug, we’ve proven on more than one occasion that coil upgrades do provide performance benefits including incre ased power you can see on the dyno. You See An Oil Leak While it sounds like there is one really bad one, there is a chance that they are all less than perfect . One of the more popular ignition upgrades on both modern and classic muscle cars is the ignition coil. Should I replace all ignition coils at once? A failing coil, unable to provide a high-voltage ignition spark, will cause one or several cylinders to miss intermediately or completely, providing less power and rpm normally seen with maximum cylinder combustion. This causes your engine to sputter and misfire or backfire. A weak-enough spark will cause a spark plug misfire, which allows raw fuel to pass through the exhaust manifold and into the catalytic converter. The gap and cylinder pressure set the voltage required for the spark to jump. A faulty ignition coil can also lead to a no-start condition. So, even the slight glitch can result in big issues. This can cause real trouble. A single coil system can affect all of the spark plugs but will particularly manifest itself with a plug that has a worn electrode and widened gap. With a massive increase in heat when raw fuel enters them. Label the ignition cables and then carefully disconnect them. Copyright © 2020 Techzillo Ltd. All rights reserved. This code is thrown primarily for the ignition coils; however, there could also be other problems that set off the code. The result of a cluster and located in a spark plug and uses the electronic did. Take it in anyway adequate voltage for proper performance, depending upon the make, model year... Blue spark between the electrodes lack of power through all driving ranges spark between the electrodes heat range require. 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