Toyota Repair: wont idle slight surge when driving, toyota corolla sr5, intake manifold gasket

Question
I have a 1978 toyota corolla sr5 liftback 2tc motor, has been driving great , today it started running rough, and will not idle runs when cold but when choke turns off it will not stay running, new cap, rotor, wires, fuel filter, air cleaner, etc etc just started doing this out of the blue, any ideas??? thankyou

Answer
It sounds like it's an intake air leak, possibly the intake manifold gasket or carburetor base gasket, check for this using a spray can of brake cleaner, spray around the suspected areas with the engine idling or have someone keep it running, the engine repm will increase and smooth out when the leak is found.