probably got a bad IAC motor
That is one of many possible causes.
Dead battery, bad starter, sieged motor. Sounds like it's electrical. On_mitch
Engine surging is usually due to insufficient fuel supply. Probable causes could be an air leak in the fuel system, or possibly a dirty fuel filter, causing fuel restriction.
head gasket? its stuffed mate!
Meteors, or asteroids.
The most probable cause is poor fuel or water in your fuel. This could also be due to the timing being out of proper adjustment.
service engion soon light is on
well it needs to be serviced...soon
The problem was not fixed with a tune up, or the light is on because it was not reset by the service station.
the computer tells it to glow.
The service engine soon light comes on when the engine computer has detected a malfunction and set a code. You need to have the system checked for codes to know possible causes.