RPM fluctuating while driving
Hi, I currently have a 2006 Ford Explorer 4x4 SUV. While I am driving the RPM will fluctuate and the truck will do a weird shimmy. It happens between around 40mph-58ish mph and again between 65-80 mph. I do have a check engine light on. Last time I got it read it was for gas cap and EGR valve. I am getting the EGR fixed but when reading symptoms of a bad EGR, it doesn't match the trucks actions.
What else could it be?
Would completely replacing the EGR fix this issue?
PLEASE tell me it is not the transmission. AHHHH
3 
Had the same problem with our heavy motorhome. Found the problem was the old fuel pump had lost pressure. Worked fine a low speeds, but would fluctuate when you gave it pedal. New fuel pump & filter, good as new.
The shimmy ? Is it 'full-time-4WD' ? That may induce the shimmy by the front wheels. It requires a ton of horsepower for the rear wheels to cause a shimmy. Don't go 80 until this problem is fixed !
由 Tom Shafer 完成的