replaced head gasket / first start up @ about 1500 rpm

check for a vacuum leak at intake. spray choke cleaner there and clean the throttleplate on both sides. if it leaks rpm will change.

all the above are ok took throttle body off & cleaned ,tried again & code p0123 & p0113 came up ,is that because i took it apart. i have not let the car run for more than 1 sec. so i really don't know where the motor will stop level

one code is intake temp to high so look for aloose aircduct connection or hole in air duct the other codeis throttle position sensor high, if you haven't got it plugged in or it may be stuck you'll need to check for that. make sure all your connections are plugged in as well before youstart the car.