Why is my 94 Camaro Z28 Engine Running Rough??

Hello Everyone! OK, I have had a problem now for many years and am very frustrated about it. I have a 94 Z28 6-speed with a relatively stock LT1 (including good ol'
Opti-Spark). Here's the problem: at light throttle (between 1500 and 2000rpm, all gears), the engine runs rough and almost seems to have a miss. I can feel the car kind of "surging" and it is really annoying. If the normal feel of a smooth running engine were described as simply "mmmmmmmmmmm", my engine would feel like this: "mmm-da-mmm-da-mmm-da-mmm-da-da-mmm". To hide the problem, I end up hitting the gas a little harder, but then it slowly -- and obviously -- accelerates beyond the speed I would like to be at and then have to slow down. I constantly repeat this pattern. My alternative is to pick a lower gear and just get the rpm's up a little higher. In trying to fix the problem, I just had opti-spank replaced (3rd time). Could a vacuum leak be causing the roughness at certain rpm's? Can the fuel pump do this (and how)? The only upgrades I have are a borla cat-back and K&N air filter, and I only have 65K miles on the car.
Thanks Everyone! Steve- snipped-for-privacy@comcast.net
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You might want to post this question on Team Camaro (www.camaros.net), you'll get lots of advice...I'm more of a first gen person, I no nothing about the opti-spark system, but the 'da' in the mmm-da-mmm-da-mmm could be a lot of things, vacuum leak, timing, bad spark plug, distributor arcing, plug wires. Probably not fuel pump unless it occurs at higher RPM's. You can always put a fuel pump gauge on it, run the gauge into the car and watch it as you drive, make sure the fuel delivery is constant.-- hope you can get to the bottom of it, Terry M.

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On my Camaro, it was a vacum leak. It ran rough in lower RPM's, and didn't accelerate evenly till 1000 RPM.
Hope you can find the cause of the problem! I have now much more fun cruising with my Camaro :-)
Regards
Dominik
Terry schrieb:

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Thanks for the suggestions Terry. If you're on www.camaros.net, you will now see a post from me there as well. :-) If my car never backfires, I am assumming that my Opti-spark distributor may be OK. As for wires and plugs, I'll have to check on that. Steve-

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If it were me, I'd put in new plugs and wires regardless if they are older, especially the wires can crack and cause arcing and misfiring. Doesn't cost much if you do it yourself. Yeah I'll watch for you over at Team Camaro...Terry M.

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How old are your spark plug wires?
Steve (Sundown94) wrote:

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