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Surging idle is USUALLY a bad pressure sensor but a vacuum leak, especially in the hose to it could do it. a throttle valve switch misadjusted could possibly do it. follow the bentley checklist. Keith ---------- > From: Douglas_Brashear@mail.amsinc.com > To: type3@vwtype3.org; aircldvw@cc.owu.edu; vintagvw@sjsuvm1.sjsu.edu > Subject: [T3] FI Ignition Problem (73 fastback) > Date: Tuesday, December 15, 1998 7:59 AM > > > > I posed this question to Jim A. a few days ago, but I figured I'd poll the > collective knowledge of the list one more time on this one (now that I have > a few more facts in hand). My 73 fasty is running poorly (stock FI, 40 K > miles on original engine, idles well when cold, when warm the idle has this > surging effect, difficult to maintain engine speeds because it wants to > hesitate). At first I thought it was a fuel pressure problem...but a few > days ago I checked the plug wires with my inductive timing light with > puzzling results. > > - the pulses from the coil are consistent (didn't miss a beat)...its a new > Bosch blue coil (tried and tested in my squareback) > - the pulses to each plug seem to miss here and there, particularly when I > try to hold an engine speed of like 3000 RPM > - the plug wires are almost new as well (though I haven't checked > resistance with a voltmeter yet) > > I bought a new set of plugs to install, just to eliminate another variable, > but if that doesn't help I'm tempted to say the problem is with the > distributor...why else would the current going in be strong and consistent > and the pulses going to each plug be inconsistent? Would a distributor > rebuild, with new points, condensor, etc. help? Any ideas? > > Many thanks in advance! > > -Doug > 69 auto FI squareback (for sale) > 73 FI fastback > 98 NB > douglas_brashear@mail.amsinc.com > > > ------------------------------------------------------------------- > List info at http://www.vwtype3.org/list or mailto:help@vwtype3.org