Instant drop in RPM

[Evholic_7]

Hello everyone! I really need your help because I hear an engine knock sound when I rev it in neutral, and the RPM drop is instantly and I don't understand why. The car is about 40k miles. Any thoughts or suggestions? Please don't send me to the dealership because I have already been there five times.

 

[SuzukiDriver2024]

At 40k miles, the RPMs shouldn't drop sharply but rather cushion at around 1000 and then settle at 750. When you were at the dealership, did they mention anything about the fuel injection system?

If they didn’t, it might be worth asking them to monitor the fuel injection parameters more closely. If they can’t find anything, it might be time to get a second opinion from a trusted independent mechanic who can dig deeper.

 

[Solas_Mage]

five trips to the dealership, that's rough. It sounds like you’ve tried a lot already, but hang in there. Maybe a second opinion from an independent mechanic?

 

[Lana]

An engine knock and RPM drop could indicate issues with the ignition timing, spark plugs, or a fuel system problem. It could also point to a mechanical issue like a worn valve or piston. Consider checking the ignition system and fuel injectors.

 

[titovicjoey]

What did they say at the dealership???

 

[SoSwiftly]

Stating you have been to the dealership five times sounds crazy. Your car needs proper diagnostics, so with your dealership, haha

 

[SwiftTraveler]

Based on the symptoms, I’m leaning toward an insufficient fuel supply. It could be the fuel pump, filter, or pressure regulator. The knock might indicate a lean mixture from not getting enough fuel. I'd suggest checking those, especially if the dealership hasn’t thoroughly looked into them. Hopefully that helps