the trans on this car is not so good, it only shifts when it wants to, i have tried every adjustment there is, either it will shift tooo soon or toooo late or not at all or stay stuck in second gear. if you want to fool with it you can see it from under the car where the gears are, there is a silver gear next to the smaller black one, there are 2 holes with allen screws in them, the one offset from the center is the adjuster, clockwise makes it shift later, counter clockwise makes it shift sooner (at least in every other 2 speed car, i have 3 with 2 speed transmissions in them). You should use 90 degree adjustments at a time and try it out. Let me know what happens, maybe i just have a bad shifter, the screw was all the way in and sometimes that compresses and messes up the spring that throws the arm out, its kinda works the same way the clutches work on the engine, the faster the rotation the more the arm comes out and grabs the next gear. <--------hope this helps you out and makes sense

You need a short plug not a long one most cars use the same plug. you remove it with a glow plug wrench.