is this just a spark plug issue? I have had the car for about 2 years and dont recall them getting replaced.
My car has 90000 miles.
My car has an automatic transmission.
It sounds like you may have a couple of issues going on here. Your idle should generally be around 800 RPM’s when the engine is warm and not at a high idle during warm up (in which case it may hover around 1,200-1,500 RPM’s). You may have a dirty or faulty idle air control valve which is a valve on your engine’s intake that reads the air intake and relays this information to the ECM which then uses this to make adjustments to the fueling of the motor. When this is dirty or not working properly, it may cause the idle to fluctuate erratically and in some cases die.
It sounds like you may also possibly have a clogged catalytic converter which may be limited your engine’s ability to accelerate as you describe. As you may already know, the catalytic converter converts toxic exhaust gases into less harmful pollutants that are suitable to be expelled into the atmosphere. When this is clogged, this causes these gases to be backed up into the exhaust system not allowing the engine to breathe properly (think of a backed up sink). When this happens, the engine is forced to work much harder to expel these gases. This often results in the engine bogging down, hesitating, shaking and causing very poor fuel economy. This should also cause a check engine light to come on as the O2 sensors should be reading the incorrect amounts of oxygen in the exhaust gases if this is your problem. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your catalytic converter.
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