hey i have an 01 z24 and when im drivn it stutors like if it a miss fire, this usually happens around 1500 and 2000 rpm n more when going uphill or focing the engine. What can this b? i recently changed the furl pump n filter but same problem even mpg went up =).. im thnkn if it can b a vacuum prob, sparkplugs, injectors, and doubt its timing belt but need help plz its a 5 speed with new trans n happens rarely on 2nd gear n most of da time on 3rd 4rd 5th gear

start with the easy stuff. like plugs

also how old is your o2 sensor?


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Primer Counts as Custom Paint Right?
BTW: This is my Sig.

yea ima check da plugs tomorow.... n o2 senor i thnk is stock with 113k miles

I would suggest o2 sensor, and if changed go with the expensive stock ac delco sensor, if not, your problem will never quit. I know this from experience.


98z24, lowered 2", aem intake, cat-back striaght pipes!, cop ligths in the front and rear, 18" liquid metal's, primer black, tint, full audio and video.

o2 wouldnt cause that

horsepower is the force that determines at what speed you hit the wall, torque is the force that determines how far you take the wall with you after you hit it.

Sounds like an ignition-advance problem to me... Like it's getting too much.


Go beyond the "bolt-on".

the thng is that after passing 2000rpms it runs well n picks up fine but i did get a new fuel regulator the old one threw in too much gas and the car wuldnt start.... im lost for this problem sometimes when i shift it lacks until i pass like 2200 2300 rpms...

i used to have teh same problem and it turned out ot be a misfire


____________________________________
Primer Counts as Custom Paint Right?
BTW: This is my Sig.

well i changed da plugs n the set of wires from ac delco because two plugs where burn but problem got worse it stutors a lot more before picking up... i have a feeling it can b the fuel injectors.... if it was a misfire the check engine light would come up and mine is off thats why i think its more of a mechaincal problem

wires? I thought you had a 2.4?


____________________________________
Primer Counts as Custom Paint Right?
BTW: This is my Sig.

Injectors in computer-controled years aren't really that mechanical. But, they may be plugged-up. Still, I think it's getting too-much advance in the ignition timing under tip-in, and whatever octane you're running is exasterbating it (Making worse). Try a tankful of a lil' higher octane fuel & see what happens. If it persists to the same extent, then pursue injectors needing a professional cleaning. If it persists to a lesser extent, then go even higher with the octane fuel you run. But don't bother going higher than what's "Premium" at your average local pump, as that'll be a temporary fix that'll cost you way more in the long run than you might want to spend. Plus, I don't think you'll need gasoline with more than 93 octane points anyway.


Go beyond the "bolt-on".

there not really wires per say but its wat carries da current to da spark plugs from dat metal part on top of the car dat says 2.4 (m forgot its name)

well i have always used 91 octane or atleast 89 cuz i dont like 87 from chevron cuz i work their...

im gona change the injectors or getn cleaned but i have them off....

"it's getting too-much advance in the ignition timing under tip-in" how van i check this, what is meant by this?

thx for your help

Tip-in: The initial opening of the throttle off of idle. Usually the largest amount of advance the engine sees occurs during this, to help accelerate it when moving the vehicle it's in from a stand-still, which is in average the heaviest load it'll see. Too much advance (along with too hot of air being breathed in, and too hot of operating temperature & too low of octane of fuel used) will cause detonation, which is what sounds like is occuring to you. The only way to check it is with a Scan-Tool, or an HP Tuner setup, connected to the ALDL (Assembly Line Diagnostic Link) located under the dash. But if you don't already know what the values (Programed settings) for your engine are under certain conditions (Throttle opening, engine speed, vacuum level, etc...), then maybe you shouldn't bother with it & just take the car to a good service-shop.


Go beyond the "bolt-on".

k that sounds better.. i do have a scaner but i dont know wat the specs should b at..