Car Information:
Ford F150
Year: 1994
Engine Size: 5.8L
Trans: Automatic

Issue / Question:
High idle – changed the IAC valve three times, the last time I scraped and vacuumed out the carbon. Each time it runs great for 2-3 days, then the idle revs up really high. I turn the truck off, wait for a minute, and then turn it back on and it runs fine for a few minutes then idles high again.

It sounds like the ISC is trying to compensate for an intermittent vacuum leak. Its possible that the EGR valve is sticking open for carbon.

For professional auto repair and auto services in Orlando you can call our shop today at 407-629-2661.

Magic Mechanic
1432 Lee Road OrlandoFL32804 USA 
 • (407) 298-7447