Hey guys, long time no see... got a problem, lately ive been noticing a very VERY subtle stutter in performance at WOT in the higher RPM range... almost like a slight surge of power i guess you could say. And when i come to a stop, and rev the motor to about 4000 RPMs or so, the car vibrates pretty badly... not so much as to say my car is going to shake apart, but bad enough... not so sure of how one of these should feel, since its been a while since ive driven an LT1 aside from mine.... anyone else have a nasty vibration at 4 grand? I was thinking this could be my torque converter..... but ive been getting intermittent SES lights, that only turn on every once in a while when im cruising at very low RPMs, then go away after either driving for a while, or resetting the ignition switch. O2 sensor? i dunno... someone make sense of all this before i go mad! lol

 

driveshaft balance? spark plugs? u joints?

 

spark plugs and wires are brand new, so are the u joints... driveshaft? hardly... could be what im feeling at high speeds, but should have no affect on my revving at a stand still...

 

You are most likely floating the valves causing the lifter's to pump up and hold the valves open when the RPM's come back down.Checked valve springs lately?

 

I have a similar problem at low rpm, a slight stumble but the car is fine at high RPM. Also, the valvetrain is a bit noisy. My motor has 4K on it w/ a hotcam kit. My RPMs stay around 2K when coming to a stop for a few secs before dropping. I heard issues w/ hotcam springs in LT1 heads, possible valvespring issue?

 

The stutter problem is most likely a sensor going bad. MAP sensor, TPS, something along those lines. Get it scanned and youll find out. Vibration could be something driveline related, torque convertor possibly, also might be a mount, motor, trans.

 

I would bet its the opti-spark. Just my 2 cents. The MIL light if I'm not mistaking is to do with the EGR Valve. Same thing happened to my car if i drove at a constant speed for a long duration of time. Your vibration is hard to say maybe it is the exhaust vibrating on someting.

95 Z28 Black 6-speed Hypertech Programmer w/cartridge, Moroso Cold Air Intake, Smooth Bellow, Ported Intake, Adjustable Fuel Pressure Regulator, Magnacore Wires, Edlebrock Headers, High Flow Cat, Borla Cat-back, Hurst Shifter, Spec Stage III Clutch, Upgraded Transmission, Bilstein Shocks, Eibach Pro Kit, HPM 4 Point Strut Tower Brace, HPM Sub-Frame Connectors, HPM Trailing Arms, HPM Panhard Rod Bar, HPM Adjustable Torque Arm, Poly Bushings, Hellwig Sway Bars, Richmond 4.10's, Torsen Zexel Diff

 

Exhaust vibration would not cause the car to shake as much as he described unless the manifolds detached themselves from the head, or the cat detached its self from the rest of the exhaust and hes running wide open. Its something driveline or mount related, my best guess.

 

yeah, i was thinking the torque converter.... because like i said, its vibrating when i rev it at a stand still, so it has to be something from the torque converter back... although i do get a rumble as well at high speeds... pretty nasty one too lol probably just the same thing though... as for the sputtering? im going to have the light checked out soon.... thanks a lot guys

 

*bump*

 

someone mentioned the EGR Valve, and then of course the torque converter, what are some other warning signs for those being bad? and since i dont see a sensor on the EGR, how would that cause my SES light to come on? i mean ive heard of power surges with a bad EGR, but the SES light is new to me...