My tercel started suddenly idling very rough yesterday. It has been idling fine up to then. I looked for loose hoses and checked for loose plugs but doesn't seem to be any. Could a plug have gone bad that quickly or what else could it be!,
There many problems that can cause a rough idle. A bad spark plug, spark plug wire, coil, vacuum leak, a engine valve problem related to the valve, spring and cam shaft lobe.
How many miles are on the vehicle?
The first step is to find out which cylinder is malfunctioning.
I would need the year, engine size and any important information you can give me to help you fix this problem.
You can also go to Auto Zone and they will scan the engine computer for any trouble codes related to the problem and I would need those codes to help find the problem.
Get back to me when you can and we can diagnosis the problem from there.