Hi there,

I have a new-to-me 2004 S2K and when I come off the brake and quickly stomp on the accelerator (wot) between 4-5k rpm, I notice a single jerk or stutter followed by continuous acceleration. Is this normal? Here are some videos, please turn on the audio: https://imgur.com/a/jc7GCSf.

-I cleaned out my MAP and nothing changed
-car idles smoothly
-no issues with gradually pressing the throttle, only happens between those rpms when I stomp on the accelerator
-has new injectors and spark plugs (before I purchased the vehicle)
-vehicle has AEM CAI
-some unknown drone-y cat back exhaust

I'm a bit new to manual driving so I'm not exactly sure what's going on. Thank you for time!

 

Were there any issues the previous owner mentioned? Did you test drive the car before buying it?

Thanks!

 

Nothing was mentioned by the previous owner. My fault, but when I did the test drive, I rode it in all manners except stomping on the gas.

 

Check the differential mounts. When one or more mounts are worn you get the jerking on acceleration, if the IACV is dirty and you have bad diff mounts you get low speed bucking.

 

What gear are you in? Are you in 4th? I don't see the hesitation in your video. If too high a gear some hesitation seems normal.

Our cars have little power below 6000rpm (VTEC) and you're way below that threshold. Keeping with it's pseudo-race car image you need to rev the ***s off the engine to get any power. It's part of staying engaged with the car although it's disconcerting until you get used to it. To get any power at 42mph you need to be in 2d gear and 6000rpm the threshold for VTEC. If that seems too low a gear at least try 3d gear.

VTEC (6000rpm) thresholds at WOT:
1 gear 28mph
2 42 <-- your speed but rpm is only about 4000
3 58
4 75
5 92
6 113

--- Chuck

 

You are aware how the VTEC operates and how you get a distinct power pulse all the way to redline once engaged? Is that the "jerk" you are referring to?

 

Thanks for the reply! The speedo is in km/h but I see you what you mean. The videos were taken in 2nd and 3rd gear. I think the audio in the video depicts my issue better. When I WOT, the car surges, then it seems to cut power/hesitation for a split second, then accelerates again. This doesn't happen when I gradually press the gas. Is this normal behavior between 2-4k rpm in first through third gear?

 

You're noticing a difference between a "stick shift" and the automatics you're used to. Your profile notes you're in the USA so I wasn't looking for Km/h on the speedo. VTEC engagements in km/h would be as below but regardless you tach shows you running on the "economy cam," not VTEC and the car suddenly getting a big gulp of air when the throttle body opens takes that half-second to figure out what you're doing.

VTEC (6000rpm) thresholds at WOT:
1 gear 28mph 45kmh
2 42 67
3 58 93
4 75 121
5 92 148
6 113 182

Also note the AP2 engne 8200rpm rev limiter won't let you hit 60mph in 2d gear, where it cuts out at 58mph (93km/h) so don't panic on that expressway on-ramp when the engine "cuts out," you didn't break anything, just shift! (We've all been there!)

The so-called (and wonderful) VTEC-Yo! kick only happens at WOT and 6000+ rpm. Both being requirements. WOT below 6000 should behave as you're describing. You can cruise all day long at revs higher than 6000 without engaging VTEC if there's no load on the engine. Cruise-control all day long at 70mph (113km/h) and you're still on the economy cams.

Run the car at full throttle (and 6000+ rpm!) and see how it performs.

-- Chuck