dmd
Well-known member
In the last few weeks my '96 LT4 has been developing a new problem. Below 1500rpm and at throttle inputs >~20%, it gets the hiccups. I don't want to call it a misfire, because it is much more severe. It is as if the ignition is being shut off for a fraction of a second and it's a very harsh jerk through the powertrain. The computer doesn't seem to see it, as it's not tripping the SES light when it happens. So thinking outside of things from which the ECM has feedback, I'm betting it's ignition related - so that would point to the Optispark starting to go, but these don't appear to be symptoms usually associated with its impending failure. So my question is, how likely is it to be an Optispark with those symptoms, and what else might it be?