Low idle or fluctuating idle Ford
Fix low idle or fluctuating idle on Ford Vehicles
Ford has issued a service bulletin #10-21-6 to address a problem a low idle or fluctuating idle on the vehicles listed below. If your vehicle matches the model year and build dates listed below, Ford recommends installing a new throttle body to correct the problem.
Models with low idle or fluctuating idle problems
2010-11 Ford Focus, Fusion, Taurus
2010 E-150, E-250, Edge, F-150 trucks
2010-11 Ford Flex
2010 -11 Lincoln MKS, MKZ
2010-2011 Lincoln MKT
Engines involved that have low idle or fluctuating idle
The service bulletin only applies to these engines: 2.0L, 3.5L (w/o GTDI), 3.7L, and 4.6L 2-valve.
Low idle and fluctuating idle symptoms and trouble codes
Ford reports that the symptoms show as an idle speed that drops below the recommended speed or the vehicle exhibits a fluctuating idle. The vehicle may or may not store the following trouble codes:
P2111 Throttle Actuator Control (TAC) System Stuck Open
P2112 Throttle Actuator Control (TAC) System Stuck Closed
Affects only those vehicle with these build dates
2.0L 2/11/2010 thru 8/2/2010
3.5L and 3.7L 3/1/2010 thru 8/3/2010
4.6 2-valve 5/7/2010 thru 8/2/2010
Replace throttle body with updated design to fix low idle or fluctuating idle
Ford has issued updated parts to fix the problem.

7T4Z-9E926-FA
7T4Z-9E926-FA Electronic Throttle

8S4Z-9E926-B
Electronic Throttle
©, 2017 Rick Muscoplat
Posted on by Rick Muscoplat