Since we're on the topic of engine judder. I have another similar problem.
Back in January I changed the clutch, bearing, pressure plate (the whole lot) on my Corolla AE101. Ever since then I've been having this random "pulses" from the engine whenever the engine is on idle, and the clutch depressed while in first gear.
scenario (in sequence):
- you are in a jam, and you have first gear engaged, so you crawl through the jam.
- when the car in front stops, you depress the clutch pedal to free (BUT you are still in first gear).
- the engine would "Pulse" sometimes. Its like the gear is not totally free and it keeps tugging at the car.
- Solution is to pull the gear out from 1 to neutral, and it will be gone.
Any ideas? It would not happen all the time. just that it would likely happen when it gets hotter. I have changed the clutch pumps last week, but it still happens.