RX7Club.com - Mazda RX7 Forum - Fixed my surging/ bucking problem

My car had a tendency to surge/buck (as in jerking back and forth)only under light throttle after being run for over 30 min or so. I noticed numerous people seem to have the same problem.

Basically these are some maintenance items I did a few weeks back, not sure what actually fixed it, but I haven't had the problem since :)

1. Replaced the vacuum hose leading to the boost sensor. (my original vac hose was kinda cracked).

2. Switched oil from non-synthetic to mobil 1: 10-30. (I noticed my idle at start-up no longer oscillates by 200 RPMs before the car warms up)

3. Adjusted idle down, so the car idles at about 700RPM -750RPM or so when in gear and not moving. This is when I first start the car, and after the accelerated warmup sequence or whatever its called.(before my car was idling at around 900RPM in gear at startup)

If I had to guess, #2 or #3 probably fixed it. Since I only seemed to have the problem when my car was fully warm, maybe my old oil was losing viscosity too fast and causing other problems(10-30 non-synthetic oil).

#3 may be related because the problem only occurs under light acceleration. So the problem might have something to do with the way the throttle works. (BTW I never touched the TPS, only the idle screws)

Or there might be some function with the sensors or ECU or some thing that might be affected by the setting of the idle <--bla bla, talking out my ass;)

Hope this helps someone