2013 Ford Explorer, 3.5L Ecoboost, 110,000, auto.
Ran just fine before a plug change, had the plugs changed and first cold start it ran rough and the idle would rev up and down, cycle or surge 1000-2000RPM range and then settle down after 30-40 seconds. On a warm starts it has no problems. When driving it runs fantastic actually. The rough idle went away after a few weeks, now just does the up and down rev until it settles down. If you hit the gas a little it seems to settle down quicker I’ve found.
My mechanic can’t figure it out and he’s been very reliable (reminds me of you) and has been working on my cars for years. He checked the Mass air flow sensor, cleaned it, cleaned the throttle body and the fuel trims are good, no codes at all.
Any ideas?
Thanks!!!
realize when you change the spark plugs on those you have to move a lot of stuff could easily have knocked the vacuum line off or worst case scenario the core line plugs once removed since they are rubber and plastic parts can crack and short out a little and need replacing
