weird jerks, is it my clutch?

['97z28m6]

ok i've got a 97 z28 and when ever i WOT in any gear, as soon as the rpms get around 4000-redline my car violently shakes. i've read a lot about when your clutch is slipping the rpms just steadily increase faster then the speed of the car, but mine doesn't do that, the rpms jolt and it feels like riding in a car with someone who has bad footwork in first gear. the other thing is that it only does this when the clutch seems to be warmed up, if i wake up one morning and get into the car and take it down the street and WOT it, then its fine, untill it gets warm and then it does the jolting thing again. i don't think its the engine at all because if i am in neutral it revs very smoothly all the way up with no backfire or bad sounds at all? so is it the clutch guys, also car has 104k miles and the clutch was last replaced around 73k miles with a stock replacement. sorry for the long post, just want to make it clear whats wrong

[Black93Z]

it could be a sensor such as MAF, O2's, IAC, or your fuel pump could be going bad. does it have a high idle then calm down on a cold start? does it have a hesitant start warm or cold?

['97z28m6]

well thats funny, my car did have a hard time starting when i had low gas, but i just replaced the fuel pump about 2 weeks ago with a walbro 255lbhr pump so i don't think its that anymore. also not to mention the car hasn't been doing the jerky thing the entire time, its only been doing it for about the past 3 weeks. sometimes my car does seem to idle high but it might be the tach, it always sits about a millimeter bellow 1000 rpms

[CamTom12]

Might scan log to see what your motor's doing. Might be the clutch slipping though. Stock clutch... How much power are you making?

[LS13RDGEN]

Only does it when warmed up?
Have you checked or bleed the clutch hydraulic fluid?

[Black93Z]

do you have a piggyback tune? like what i had, where you keep your stock PCM and then plug the new chip into your PCM then plug the new one into the circuit board? if so it could be going bad, i just had that problem, my aftermarket piggyback chip just went bad and i had all kinds of problems.

['97z28m6]

no, no tune, stock computer, i dont kno the exact power numbers ive been putting down, but i have CAI, new elbow, BBk 58mm tb, pacesetter headers with true duals, and a walbro fuel pump, i'm actually going to check the clutch fluid tomorrow morning so i'll let u guys kno on that tomorrow

[CamTom12]

maybe too much fuel? That's how mine felt after I threw the 42#'ers on there

[Black93Z]

i just put in the same fuel pump that hes got, finished the install yesterday, even with the stock non adjustable FPR it shouldnt over power it so that it gets too much fuel

['97z28m6]

what if my FPR wasn't working correctly, would that cause it to be giving me to much fuel?

[Black93Z]

yes if it wasnt working correctly then it could be providing your engine with too much or too little fuel thus the stumbling and chugging and everything that your experiencing

['97z28m6]

well sweet, i think ill go put a post on lt1 section asking whats a good aftermarket regulator to get thanks for yur help so much!!