Would new spark plugs help improve idle smoothness?
- Thread starter Soft Cars
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Year, make and model of your vehicle? Mileage? Rate of oil consumption? Have you checked for a vacuum leak? Condition of motor mounts?
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New plugs might help idle, depending on how many miles you have on them. If it's a 4 cylinder, it's cheap and easy to change them to see if it helps.
This.
Plugs, throttle body gotta start somewhere or plugin a diagnostic tool.
I recently replaced the 2 upstream O2 sensors on out Tundra with 211K. Rock solid idle, smoother acceleration, etc. Placebo? Dunno but it seems better.
An intake gasket leak is just the thing to throw your idle quality off. Max vacuum, minimum fuel. Spray some WD40 in the area while the car's idling to see if it changes by ingesting the "fuel."
It can't hurt and it's a good place to start.
Make sure the mass airflow sensor is clean as well.
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If plug is fouled out or not firing the same, could be affecting it.
You got slight engine shake at idle with no misfire? Sometimes the spark plug boot isn’t on all the way. Been there done that..:
You got slight engine shake at idle with no misfire? Sometimes the spark plug boot isn’t on all the way. Been there done that..:
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But if you’re going that route. Plugs AND WIRES… Plugs wires and coil if you’re really just eliminating that part of the equation in a tune-up.
And no aftermarket coils….
And no aftermarket coils….
If you have really old worn spark plugs in say past 100,000+ miles or less miles if you had old technology copper core plugs of the 80's that you can still buy.
Since I always keep somewhat fresh plugs in my turbo car, the only style plug I have ever found to help idle smoothness and an every so so so slight difference you can actually feel in daily driving is a HKS Ruthenium racing spark. The are also daily driver versions of this style plug that I can't tell you will feel the difference, but chances could be better then an Iridium plug. This feeling is there when going from a HKS Iridium Racing plug with 5,000 miles to a Ruthenium Racing plug new. I switch out plugs at 30,000 miles. $35 a plug before inflation. Coils close to the 40,000 time frame. All my family's cars have the daily driver Ruthenium plugs in them now at around $55 to 65 for 4.
https://ngksparkplugs.com/en/products/ignition-parts/spark-plugs/ruthenium-spark-plugs
Since I always keep somewhat fresh plugs in my turbo car, the only style plug I have ever found to help idle smoothness and an every so so so slight difference you can actually feel in daily driving is a HKS Ruthenium racing spark. The are also daily driver versions of this style plug that I can't tell you will feel the difference, but chances could be better then an Iridium plug. This feeling is there when going from a HKS Iridium Racing plug with 5,000 miles to a Ruthenium Racing plug new. I switch out plugs at 30,000 miles. $35 a plug before inflation. Coils close to the 40,000 time frame. All my family's cars have the daily driver Ruthenium plugs in them now at around $55 to 65 for 4.
https://ngksparkplugs.com/en/products/ignition-parts/spark-plugs/ruthenium-spark-plugs
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Plugs after 2.5 years? No way, not unless something else caused them to fail prematurely.
As other's have asked, what kind of vehicle? If the plug wires weren't changed in '20 along with the plugs, they could certainly be due and be the cause of a hiccup at idle. As could a small vacuum leak, as mentioned here.
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