ok so for some background first

94 z28, rebuilt 355 to stock spec more or less, le1 cam, bbk shortys-the longtubes hit the crossmember all the time, 1.6rr, aerochamber, slp intake, msd opti, autolite plugs, some massssssive sized taylor wires, and i think about everything else is stock, and underdrive pulley but a bigger alt pulley
also its a 6sp with 3.73 gears and the gears werent installed right so they make noise...they r in right now but still do the noise but will be repalced as soon as i get this dang problem fixed


basically this things making me mad now, i have been trying to tune it for forever with solomon and thankfully hes patient, but im clueless as what to do at this point.


basically the car idles fine, a lil high i think like 900ish. revs fine, but starting in first gear feels like im starting in 2nd, i dont think the cam is that big, but my stock cam in there had more first gear start up power for sure. thats not the main issue tho

the main thing is basically when its under 2k rpms the engine and tranny shake like crazy! motor mounts and trans mount r fine, ive checked those. you cant feel the car shaking unless you put your hand on the shifter, then u can feel it pretty good. this is mainly annoying on the hwy in 6th gear bc its under 2k rpms unless im doing like 90 if u ease the throttle it will accellerate and then smooth out, but if u punch it like wot it sputters and feels like its got a miss or something, but still continues to accellerate it just feels like crap. but also i think it needs to be said that if you punch it from the beginning in first the car will just take off, but still doesnt quite feel as fast as my stock cam.
im not really worried about the speed issue right now, i want to get the thing to run right first, im about to put the other cam in it but i figured id ask and see if anyone has any ideas for me


thanks

 

I think your opti might have issues.Do you have a friends that have an extra one,or did you save the old on to put back on?hope this helps.

 

Could be fuel related to.

 

Check your plugs wires closely. Recently my car developed a shudder like you describe (right after I did a AC compressor change) and would shake like crazy. I found a plug wire had touched a header primary and had burned through..allowing an arc to ground. I pulled the plug away and it cleared up immediately.....

 

Your injectors might be clogged, easy to get to and look at so might as well do it anyway.
Had a similar issue last week with mine and injectors had rust piling up inside them. Only about 3 of them, but when I cleaned them it ran perfect.

 

ill check injectors

on the opti, it came on the car. it runs so good at high rpms so i dunno, well, good compared to lower at least, i still dont think its at full potential, one of my plug wire is burned but i taped it and its tied away from the headers....i havent seen an arc from it but that doesnt mean its not there.... could this cause all that?

 

Yep...

 

Yeah definitely.
There's like 5 solutions in here and all of them are common.. and all can cause the same problem, heh. Try them all!

 

I had what I thought was a slightly burnt plug wire. I replaced it and cut the old one open. The inside wire was almost gone in that spot.

 

Well.... I feel a little dumb. But thanks for all your help. I bought new plugs and wires after work and when pulling my old plugs they were gapped at .08 instead of the .05 they r supposed to be and I found that the one wire that I thought was the issue wasn't. There was another hiding that was burned all the way through. Needless to say it's a totally different car now. I apologize if this is a common deal but thank you so muh for the suggestions. I have been fighting this for a month and a half thinking it was my tuning and header fitment issues. Thanks again!!!!

 

Nice, at least you got it fixed!
I had a wire when I first got my car that was plugged into the bolt, next to the spark plug. Obvious fail was obvious.

 

haha, well wanna know what makes it worse, is i already burnt a new wire. at least i had a spare form the other set to tide me over. i need to learn how to route them better, or just get manifolds.