I have a 2010 Toyota Corolla with 66,000 miles on it. When accelerating my car, it becomes bumpy between 20-40 miles per hour. I don’t notice this happening while on the highway. I’ve had a couple of mechanics tell me they think it could be either the coil pack, spark plugs or fuel filter. I have 2 questions. First, how can I test the coils and spark plugs to see if they are good or bad and second, do you have any other suggestions on what might be the problem? Thanks for your help!
Check tires for bulges or cupping (uneven wear across outside to inside of tire tread with high spots). Iridium spark plugs are used in all toyota engines since 2002 from factory which should last 100,000 miles. Check engine light would illuminate with a misfire code if it was bad plugs or coil pack. Shaking within the indicated speeds is most commonly a tire has thrown a weight or is separating.
January, 24, 2014 AT 4:26 PM
A coil can only be tested correctly with an oscilloscope while under load, this can be done with a live data scanner. The spark plugs should be replaced at 20,000 Km for standard or 100,000 for iridium, iridium plugs cant be cleaned or re gapped and they have a pointy centre electrode, standard plugs are cheap so replace if in doubt.
January, 25, 2014 AT 7:47 AM
I know it's not the tires. When accelerating, the car is hesitating slightly and does so while laying off the gas but only on lower speeds. On the highway is doesn't do this and it's doesn't do it each and every time I accelerate but it has become more frequent. Tires are newer and I'm positive that's not the answer. My bad for using bumpy.
January, 25, 2014 AT 3:50 PM
Check the tune related items, sounds like a misfire.