hey, my dat does the same thing at 4000 but its cool when it does that, it kinda lets you know when to change gear,when the music is loud.. also with the over heating just get a thicker core on the radiator.. unles you have the fan on the radiator

found the problem, faulty coil.
Driving to work this morning is when bad again after driving normal for 10 mins, the coil must of cut out completly going down a hill, i had it in gear trying to start it :) unfortunatly i was pumping the pedal thinking it might of been a fuel blockage .... what a mistake! The coil came to life for a short time, enough to blow the absolute shit out of my exhaust then stoped all together. Myself and the cars around me looked very pale. My exhaust now looks like a ACME product from the road runner cartoon. Anyway got Dad to pop down with some tools and luckly an old coil, which limped the car home.... minus an exhaust. Thanks for your help! Now i get the 2 inch system i wanted!

I'm with DD,give all the electrical terminals from the coil a good clean and sand along with any other joiners along the way,also give any body earths in the area a good sand and clean.
I've had similar glitches before,you gotta remember how old our cars are and these areas are generally never looked at until something stops working.
Enjoy

Tachometer going crazy indicates an electrical problem with the ignition.

Check all the wire connections, especially those going to and inside the distributor. Make sure they are tight and not corroded.

i think u need a new car, throw it in the bin!

Blocked Jet in the Carby, i only suggest it because i have similar mods and have had a similar situation with my Weber carb. Gave the 2 main jets a check and then the 2 idle jets and found the problem, crappy little bit of plastic blocking playing games with the idle jet.

Hi,
my stock a12 is hesitating when it warms up and under load. At crusing speed it seems ok. The only mod is the Pertronix Electronic Ignition with new coil, instead of the points, and i have new leads / cap and spark plugs. Its been running fine for a few months. The only strange thing is when it hesitates and im trying to rev the motor the tacho goes crazy when i know im only doing about 4000rpm. Could the coil be faulty? The motor seems to be getting hot quickly as well but the thermo fan is running a fair bit to keep it normal. Any sugestion would be appreciated, cheers Tim