My 91 w150 318 idles way to high how do I turn it down? Its a tbi Holly. The local shop told me that its controlled by the ecu and that 1500 rpm idle is just fine. Is he right? Thanks.

 

The actual idle is controlled by the computer and cannot be adjusted. The base idle can be adjusted with special equipment but I understand this is rarely if ever needed unless you replace certain parts. If you would like written confirmation just read the emissions sticker under your hood. The idle can be effected by the timing but if it is running OK I would leave it alone.