high idle: when i start car it idles so fast. why? told i need motor mounts. on 1998 Buick Century

because motor goes clunk when i shift from park gear and engine seems to shift. also told i need new catalytic converter because car sluggish when giving throttle to stop problem of high idle. auto zone diagnostic said need erg valve. confused?

1 answer
STAY AWAY FROM AUTO ZONE UNLESS ITS JUST TO GET CODES. SEEK ANOTHER OPINION FROM A GOOD SHOP