Loss of throttle response?

mokhan996

This thread might be dumb but **** it why not. Not often but time to time if I’m at a dead stop putting it in 1st gear, the revs would be so low, as if it’s hesitating. At neutral just revving a bit out of curiosity, it would hesitate as well. When I say hesitate, usually when revving you’d see the tachometer spiking rapidly, not in this case. When I did rev it at neutral, it’d hold at 2k RPM for 2 seconds. Idk it probably happened 3 times for the year and half I’ve owned it. Oil temp was at 220 if that means anything at all. Idk.. didn’t look in to it, probably thought someone here had the same issue before. Now it runs fine. Any insight?

JARblue

Sounds like heat soak but could be dirty throttle bodies/MAFs

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SouthArk370Z

I'd try cleaning the MAFs. Very easy to do. Several DIYs on this site.

Inspect air filters and change as needed.

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mokhan996

Thanks for the advice! What if it is heat soak, how should I go about fixing that issue? :/

mokhan996

Definitely gotta inspect those. Thanks for the advice!!

ZPWR

Sorry to revive a dead thread. But did any of the suggestions above fix the issue? This is the closest I can find that relates to what I'm experiencing going off from a stop in 1st gear. It seems pronounced when the car is fully warmed up at optimum oil temp and you're about to let the clutch bite into gear while just reaching above 1k revs and all of a sudden it just hangs and bogs down when engaged, while taking atleast 2 seconds to respond to acceleration when you put the foot down almost all the way.

I do have a small fix - If you first rev up around 2000 RPMs and hold it while the clutch is fully depressed and slowly engage it, it will get going normally. But I don't like this because it slips the clutch more than I'd like.

Interestingly the car accelerates fine once you're off. I get my full power & torque bands from 3k up to 7km revs but it does feel sluggish compared to when I first owned it which was about 6 months before this issue popped up for the first time. I've had this problem for a while now and have neglected it thinking it was just a minor thing that would fix itself through the ECU. But sadly it has lingered and has gotten a little worse overtime.

If it helps I've got 49390K on the odometer.

Here's some helpful info that may help:

Short trim fuel bank #2 was like over 12% positive at one point (a really hot day)
But reads normally around 0-2% after cold start.

If the source of the issue is a vacuum leak, which components should I look at? Should I also look for any exhaust gas leaks if that also causes more power loss in the low rpm bands?

Hopefully someone can shed more light into this issue. It's a weird one for sure. Also going to read up on what this heat soak problem is. Sounds worry-some.

Spooler

What is your temp getting down there? Have you done any intake mods or are you still stock? Your issue sounds like heat soak also.

ZPWR

100C (212F) deg on a hot day and about 105C (221F) light-spirited driving shifting around 5k RPM ranges. I could use a thermo gun to check temps around the engine block but I don't own one. Still looking into more videos and forum posts about heat soak. Any good permanent solution on fixing heat soak issues?

Are there any other factors that may cause heat soak?

Couple more info that may help:

- Since owning the car I have not changed/flushed the coolant which can range from 1 year to over 2 years considering previous ownership. One of my many to do lists of scheduled maintenance for my Z at the moment.

- I cleaned my TBs last year but couldn't fully clean them out on both sides as I had trouble getting them out due to the strut brace and not having the required tools.

- I've also got a minor sweat around the rocker cover gaskets both sides. Not sure if that factors into heat soak.