86 Camry LE HB with 5-spd manual.

Problem...at around 2000 rpm the engine misses and surges as if the ignition was cutting in and out. This only happens when driving under a light load and is worse when the engine is warming up, transitioning from cold start circuit to normal running. Not as bad when the engine is fully warmed up but still noticeable. Note that this problem instantly goes away when accelerating and the acceleration is quite good. It also doesn't happen when cruising on the highway at slightly over 2000 rpm, with or without cruise control engaged but you can still detect a slight irregular miss.

I've changed the plugs, plug and coil wires, distributor cap and checked the PCV valve. I used to have one of these cars 20 years ago and had the Haynes manual for it but seem to have lost it over time so I can't do a troubleshooting diagnosis. Anyone got any ideas?

Thanks.

 

Have you checked for a vacuum leak?