Acceleration issue
 

Hello, I’m a 17 yr old g35 coupe owner that wants to baby my g. Fell in love with the car the second I bought it. However I never worked up the courage to floor the gas pedal until building up enough confidence to do so. Anyways, I notice that when I floor it, and only when I floor it. My car sort of lags, sort of stops acceleration for a very quick second during it’s acceleration and then will quickly resume speeding up. I want to know what it is as it frightened me the first time. Motor shows no serious wear and the car is all around healthy. Another thing... recently after parking my car in the garage I noticed a leak near the back passenger side of the car, the color green. My father told me it might be antifreze, I’m wondering how the heck it got back there. Keep in mind the leak was very minor. Any information with this would be much appreciated thanks. Also it’s an automatic :(https://cimg7.ibsrv.net/gimg/g35driv...057abff3a.jpeg

The coolant leak may have been from another vehicle so monitor your fluid levels as a precaution but I wouldn't worry about it unless the level drops.

As for the power drop when accelerating that's a CLASSIC sign of a vacuum leak, take apart the intake tract and look for small cracks in the rubber. Replace anything that shows signs of wear, pay particular attention to the "accordion" sections and bend them around so you can see into the gaps.

There are three primary vacuum lines that develop leaks, a tube that goes from the intake pipe to the right side valve cover, a tube that goes from the left side valve cover up to the intake plenum, and a tube that connects the two valve covers at the front of the engine (top). Disconnect them and inspect them for cracks as well and verify its a snug fit with a CLAMP on each end. Replace anything that's worn. Z1 Motorsports sells some nice silicone hoses if you want an upgrade (they don't really ever wear out).

As a warning, newbs tend to overtorque fasteners, they don't not have to be as tight as humanly possible, just make them snug so you can't rotate the tubes anymore.

U sure youre not talking about the slight lag in the transmission as it shifts gears when u floor it?

Great point, I didn't even consider the shift delay if it is an automatic.

That delay is terribly inconsistent. Sometimes my car goes down one, then two gears before launching out, sometimes it jumps down two immediately (usually happens in 5th JUST under 2k RPMs). I know it goes down to 2nd as it's redline at 60mph then, but I'm not entirely sure if it's in 4th or 5th then (definitely above 35mph, so I'm inclined to say 5th). Didn't think these autos could skip gears, may have to go out for more...testing.

That actually sounds like a TCM issue, probably the transmission ground which is located at the front of the ENGINE on the timing cover at the very top. There are two wires that are landed on the timing cover mounting bolts, one of them is for the transmission. Remove the bolt, clean the bolt, the 1-hole lug (both sides) and the mounting surface on the timing cover with a wire brush, apply a light coat of electrical anti-oxidation grease, and bolt it back on.

It's a sensitive computer inside the transmission and a 100k mile dirty ground causes problems like that.

Definitely not, this issue feels like the car is getting too much air and stutters. It all happens very quickly.

Thanks for the info, now that you say it, it feels as if my car is getting too much air, it all just happens so quickly. I’m gonna try to take a video to help you guys out. Thanks for the heads up.

I’m going to see if I can take a video a upload a link for you, I’m not familiar with my car but I know for sure this issue is abnormal, (not a shifting problem) it’s all in the engine.

Upload it to YouTube and post the link here, it will embed the video automatically.

Here you go..

That looks like a clutch pack slipping, take it to a transmission specialist for a diagnostic.

It’s an automatic though.

Correct, each gear has a wet clutch pack inside an automatic transmission.