Q: Loud ticking/soft knocking in engine is worse after tune up
The engine used to have a soft tick, that would go away once the engine warmed up. I replaced the spark plugs, intake manifold gasket, and EGR valve gasket. The ticking is louder and goes in sync with a soft knocking noise. It does not go away when the engine warms up and gets more noticeable during acceleration. During idle, when you first start the car, it goes up to 1500 rpms and just doesn't sound good. After moving the gear shift and then putting it back into park, the rpms drop to 1000 and slightly fluctuate up and down.
The parts I installed were correct for this car, per the manual and OE specs.
It has a check engine light on but I pulled the code and it only specifies that there's an issue with the charging system.
My car has 103340 miles.
My car has an automatic transmission.
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The inconsistent idle is probably due to an engine management/sensor issue which would include the IAC valve but quite a few other components are possible causes, too. Mechanical engine noises stem from wear and damage. You might get some insight as to whether the knocking noise is due to main or rod bearing wear by measuring oil pressure; oil pressure drops as bearing clearances get larger. If the knocking noise goes away once the engine is warm, it could be piston slap which is not as consequential as bearing wear. If you want the mechanical origin of the noise pinpointed, please request a vehicle noise diagnostic and the responding certified mechanic will resolve that. If you desire an identification of the cause of the fluctuating idle, the same mechanic would be fully qualified to handle that as well. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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