Having problems with your 1990 Ford F150 ?
The idle is at about 2000 rpms how could i ajust it back down
The idler air control sets the idle automaticly from the computer. If it ran well before and not now the IAC valve needs to be replaced. Once its replaced the computer will set the learning codes to set the idle
And to add to that if you mess with the butterfly setting it will throw the whole setup out of sync. that is set to a specific value for voltage from the tps (throttle positioning sensor) and thousands of an inch opening on the throttle valve.
Repair Help & Product Troubleshooting for 1990 Ford F150
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