i had that same stumble problem on my car. it was a part that i thought was not it. Do me a favor unplug your maf sensor and get back to me. If the car runs fine i will tell you what your problem is.

 

I had a similar problem in my car. Do you have an MSD 6A or an AL?
I would be driving the car and it would just die so smoothly it was unbelieveable.
I also had the random stumble you are refering to I also thought it was the opti or coil. I removed my msd out of the loop and it ran flawless. Put the msd back in and the next day it started acting up. I replaced the msd and have not had a problem since. just a thought

 

MSD has been disconnected. Opti wire was green. Changed connectrs. Same thing happened. I guess I will be looking for another opti. Heading to the track now. Thanks for the ideas. I will check back at end of day.

 

maybe i type in clear letters.

 

i had a problem with a bouncing tach on my car. It was the crankshaft position sensor that went bad. Although the car ran fine the whole time I had the problem, it did turn on the SES light. That probably is not your problem on your LT1, but you could investigate that avenue. Also, AutoZone will scan your codes for free

 

There is no CPS on a 94Z..
My money's on the opti..
Like I said in the LT1 tech post, I just went thru this 'intermittant heat related' failure deal... new opti solved it.. I had tried everything else.. Grounds, connections, MSD, coil, etc etc.

 

In theory a new opti will arrive either todoay or tomorrow from Jason Cromer. He graciously went out of his way to ship one out of hurricane country on Saturday for me.

I have a fellow who can install it tomorrow evening for me.

The rental car didn't work out very well. A first round loss on Saturday coupled with my fellow points leader winning the race put me out of mathmatical contention on Sunday. I did however put a .509 light and a 16.241 on a 6.24 dial on my first Sunday victim in my Enterprise malibu 4 door with a 3.1.....

 

i had similar problems..............OPTI! i would bet money! it blew me away as i only had 9000 miles on mine! i bought a new one when i first built the stroker, just for piece of mind, i figured at 50000 miles it couldn't hurt, lol! i sold that one and put the new one in..doh! waste of money! i hope this one lasts longer! lol!!!!

g'luck!

 

Curious if new opti fixed the prob? Like it did mine?
Charlie

 

The new opti fixed the problem. However I believe the backfiring from the old opti did some damage as it seemed to only be running on seven cylinders. Performance fell from 12.0's at 110 to 12.4's at 107 and this was not because of the weather. The third gear shift at WOT would create a fall on your face condition abd then try to pick back up, like a bog... My guess is a roller rocker is off the pushrod...

However, thank you to everyone for their assistance. I am going to park the car for the season and try to start performing fixes one at a time.

Pic from the weekend is here: http://www.ihra.com/gallery/albun43/DSC_5057

 

Glad it fixed it.. thanks for the info..

 

if something like that was the prob, i think it would run alot slower than that, just my .02, check for an arcing wire.

 

Just chased a stupid stumble on a buddies car this weekend. Used a infared temp gauge to pinpoint the prob to number one cylinder had a cracked spring. Great tool if you can get your hands on one. We were dicking with possibilities of arcing wires etc.. Replaced the plugs and wire for s$hit sake since they were about due. Still ran rough swapped coils etcc.. still ran rough. Picked up my infared temp gauge shot it at the exhaust ports found all cylinders to be running around 150 degrees F hotter then #1 cylinder pulled valve cover and sure enogh problem found.
Just thought i would share it kinda a cool toy and it helps isolate a problem stumble quickly
Later
Mike