Power loss and jerking

infiniti
g35

#1

Hello, I have an Infiniti G35 (2007) with around 33k miles on it. Lately, after an oil change, I started noticing some power loss in the first gear with slight acceleration. Basically what happens is, in the morning, after I let the car warm up, so the temperature needle is close to half way up, and RPM is under 1000, at around 900. I put it in Drive, and while in first gear, and not pushing the accelerator just a bit, I notice loss of power around 1000-1400 rpm, where the rpm needle falls to 1k or less for like half a second, and then picks up and hits around 1800rpm, then falls, and then goes on. This happens every time I start accelerating after being stationary (like stopping at a light). The effect of the jerking reduces by quite a lot as I drive the car. It is still very slightly noticeable, but only the first time at the 1000-1200rpm mark.



Any reason why this may be happening. By the time I reach the garage, the jerking is not noticeable at all. It is very very slight, if you pay close attention you notice it. The garage did their electronic check and didn’t see anything at all. Any idea what may be causing this?


#2

If the symptoms are there all the time, you need another garage. The one you have can’t (incompetence) or won’t try to find the cause(s). This is NOT an intermittent problem which could be difficult to diagnose.
The easiest thing to do is a fuel pressure test. A test is more than just a test of static fuel pressure. The customer shouldn’t have to teach the mechanic how to do this tests (at different rpms and loads on the engine).
A competent mechanic will know what other diagnosis to perform.


#3

Thank you. I will be taking it to Infiniti and have them check it out.