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Matt, Engineer
Category: Nissan
Satisfied Customers: 21977
Experience:  BEng hons Mech engineering, worked in auto industry for 22 years on engine, transmission and suspension design
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My cars rpms are fluctuating and it won't go over 20 mph.

Customer Question

My cars rpms are fluctuating and it won't go over 20 mph. The needle is bouncing up and down and the device engine light is on.
JA: Do you have the trouble code? Do you have a code reader or scan tool?
Customer: No I do not. I drive a 2013 Juke.
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: No, I don't know how to work on cars. I'm going to get the oil changed and the fluids topped off. I just bought it recently and think maybe the lag owner hadn't changed the oil in a while.
JA: Anything else you think the mechanic should know?
Customer: No, it was working just fine and then it started stalling all of a sudden.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Nissan Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Nissan
Expert:  Matt replied 1 year ago.


ideally the next step would be to plug a scan tool into the car to read off the fault code thats turning on the light

this will point to the fault and greatly reduce the diagnostic time

however from your description I'd say its sounds like a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the injector rail (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

Customer: replied 1 year ago.
My car is completely full of fuel. I don't think the fuel level is the issue. But thank you! I will try what you suggested.
Expert:  Matt replied 1 year ago.


I think its not the amount of fuel in the tank but rather the electric pump that pushes the fuel through from the tank to the engine

work though my suggestions and get back to me on this post

Customer: replied 1 year ago.
I will. Thank you!
Expert:  Matt replied 1 year ago.

no problem

just get back to me on this post

Expert:  Matt replied 1 year ago.


do you still need help?

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