Hey everyone I have a g35 2004 automatic sometimes after I press the gas padal the rpm suddenly drops then returns to where it normal would be.. It was happening alot then I changed the throttle body and the system occurs less but still happen... what could it be? Should I clean the maf sensor and check for vacuum leaks...
and the drop of rpm only happens when i am in drive never in park

 

Vacuum leak on the brake booster line or the brake booster itself. There's a 1-way check valve on the rubber line just before the brake booster that you should inspect as well.

Does it also change rpm when you turn the steering wheel?

 

yes it always changes rpm when steering the wheel in park
and when in park the and pumping the brakes the rpm goes up

 

If the rpm makes a significant drop JUST from turning the steering wheel then your power steering pressure sensor is probably failing.

 

Is there anything else it could be? Just order a new brake booster hose and brKe booster valve

 

Troubleshoot the issue and find the leak. Don't just start throwing parts at the car hoping something fixes the problem.

Start at the intake plenum where the brake vacuum line leaves the plenum and goes into the battery box, look for rips/tears or loose fittings on that vacuum line. You can disconnect it from the upper plenum and plug the plenum to see if the problem goes away. This will verify that the issue DOES lie somewhere in the brake vacuum system.

 

any other ideas because I just this and changed my brake check valve but the problem still occurs
Here the video that my car is doing
https://youtube.com/shorts/Pam9vkzVMKs?feature=share3

Could it be something with the transmission because when I Rev it in park it's totally fine... only in drive does it act like that... and i Changed the crank sensor

 

I don't see what the problem is honestly? It falls to 650rpm which is the idle target, then it hunts back to 1000 since it's in gear.

Was it doing something differently before?

Does it hold a steady rpm and drive normally?

Did you resolve the rpm drop related to turning the steering wheel?

 

when the car is warm and in drive after I like go the gas pedal the rpm drop as normal but as soon as it hits 1000 rpm it drops and goes back up...

Yes it would drop slowly no jump in rpm
Yes it holds a steady rpm and drives normal
Yes I changed the steering sensor

 

Hrmm, I know this sounds like an odd troubleshoot but have you checked your transmission fluid level?

When driving at around 10-15mph when you stomp the throttle is it immediately responsive and does it grab the correct gear and accelerate normally?

What happens if you stomp the throttle at 10mph and then immediately let off the throttle?

 

Yup I checked the tranmission levels it was good.
Yes it is immediately responsive
once it hits 1000 rpm it drops and come up