Join Date: Mar 2002
Location: Austin, TX, USA
If you talking about an idle issue there are several potential causes. For now, I've got another suspicion. Do you believe the problem is occurring at a specific throttle position? The throttle position sensor can cause odd behavior like this. Try and determine if the surging occurrs with approximately the same amount of throttle. When it surges, if you let off slightly or apply throttle slightly does it quit?
There is a way to test the throttle position sensor. It involves back-probing the TPS connector with a couple of straight pins and measuring TPS voltage with the ignition on / engine off. You apply the throttle by hand, slowly and evenly and watch for glitches on the digital volt meter.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI