radiocrash

iTrader: (3)

I searched for an answer to this but my question isn't completely answered.

When I'm driving around normally, every time I go to change gears the throttle blips a couple hundred rpms. This isn't due to to my foot still being on the gas because I've taken my foot completely off the pedal, pushed in the clutch and it happened again. Figured it may be due to momentum and the monstrous dual mass flywheel, but even after my JWT flywheel it still happens. Can't be the ECU because as far as I know that technology only exists for downshifting, and only in z34's.

What's the deal? I've seen many other videos of z's as well as z's in person, none of which seem to do the same thing.

Here's a video:

350zHalleck

iTrader: (1)

That's weird.

Jah70

That is very strange. The only theory I can come up with is maybe the gas pedal is sticking slightly? Try slightly revving it in neutral to see if the rpms doesn't drop immediately when you get off the gas.

radiocrash

iTrader: (3)

Tried that. No problem there.

I'm stumped.

Italianjoe1

iTrader: (6)

vacuum leak or faulty TB most likely, allowing a little air in when you are off the pedal. When you release the load on the engine by pushing in the clutch it jumps up and then the car corrects back down.

radiocrash

iTrader: (3)

Could be a vacuum leak. Sometimes at idle the car almost wants to stall and it idles kinda rough. However my tuner told me it was "just the way these cars are"

I also thought it could be running pretty aggressive due to test pipes

Italianjoe1

iTrader: (6)

Test pipes shouldn't change anything.

Clean the throttles and see if it improves, check for any exhaust leaks before the primary oxygen senors or any vacuum leaks on the intake manifold.

Bigsyke

I thought this was because of the drive-by-wire system? I have the same issue. I have to release the throttle and wait 1 second before pressing in the clutch, else the rpm's pop up about 500rpms. Stayed the same after JWT clutch flywheel..So this isn't normal? --It makes driving smoothly difficult.

winchman

Probably something to do with that crappy-sounding exhaust system you've got on the car.

carfanatic63

My car does the same thing as well. I may try to clean the throttle body and do it. I always assumed it was the drive-by-wire. I still wish that the car had a normal throttle cable

radiocrash

iTrader: (3)

Yeah that would be nice, huh? I'm gonna clean the MAF sensors first and see if that helps.

Italianjoe1

iTrader: (6)

I finally watched the video and I don't hear anything. Might be your imagination.

Have you driven another car to see if it's the same?

radiocrash

iTrader: (3)

Only other standard cars i've driven haven't been z's. It's definitely there though. Listen closely it's especially noticeable on 2-3 and 3-4

JERZ350

iTrader: (2)

My car has always made a similar sound to that when I let off the gas ever since I put on my Borla exhaust. I had the car on the lift and had my friend rev it up while I was standing underneith and the sound came directly from the H (X) pipe. I think it's turbulence.

PerfZ

iTrader: (3)

My '03 does that, about 2-300 RPM's but I've gotten used to it. Really doesn't affect driving, I just notice it on the tach.

radiocrash

iTrader: (3)

Hmm I guess it's not all that uncommon after all. I'm not gonna lose sleep over it then.

calibredz33

i think is has to do something with the potential inertia of having your foot on the throttle, then stepping on the clutch to quickly... when i first got my deR it did it, so i tried being more precise when i shifted. i wouldn't, unless i'm running her hard, depress the clutch so closely to letting off the throttle and the problem was solved. the extra quarter second really begin to make a difference.

radiocrash

iTrader: (3)

i think you're right. i just took her for a spin and tried being super careful about that. it seemed to help, so it could just be my own bad habit that's causing it.

Italianjoe1

iTrader: (6)

Yeah for emissions reasons the car doesn't snap the throttles closed, it sets them down smootly. So if you are abruptly lifting and stabbing the clutch, the engine is still producing a little power as it tapers off and it will climb a few rpms.

calibredz33

really? ^ i mean that makes sense, but eww. lol. hmm... looking at going machanical throttle body. just looking.