Matthew

About your engine surging: I had = similar problems on my 2.1 Digijet. Like mine, maybe your system is = also feeding excess air past your throttle body which means one or both = of 2 things are faulty: 1) Idling control unit (behind right tail-light = cluster  2) idle valve (sits right on top of engine).

Try removing your control unit. = You may have to adjust your idle screw to keep the engine going: bring = it to just over 1K rpm at hot idle. Now ride around for a few days and = check whether you are still surging. This worked wonderfully for me, = even with air-con!

FYI, the control unit controls = the idle valve which allows air past the throttle body to keep the = engine from cutting out under load, ie. air-con, power steering. A = fluctuating idle means that the valve opening is = fluctuating.

Good luck!
Nigel
Cape Town, SA
89/90 caravelle syncro