Hello everyone... Recently my van started to hesitate while accelerating, usually within 15 minutes of driving it. The tachometer goes up and down. It usually goes back to normal if I let go of the gas pedal (which doesn't work while it hesitates, I step on it, but nothing happens) and let it slow down to about 35 MPH. So far, I changed the spark plugs & wires, fuel filter, air filter. A friend told me it could be the oxygen sensor, what do you guys think?!
Thanks in advance for your responses... :-)