My ranger jerks
I would begin by checking for any codes and checking fuel pressure. There is a check valve in the fuel system that could fail; failure results in low fuel pressure when starting and can cause a hard start condition. With that in mind, you can cycle the key several times before starting to rule this out. Leave the key in the run position for maybe 3-5 seconds then repeat. Get a good service manual/CD which has detailed information on how to perform pinpoint tests on those sensors. Usually throwing parts blindly at a problem proves to be an expensive form or hit and miss repair. BTW, what exactly did the "pro mechanic" do for diagnostics?
A few more questions:
Does this only happen on a cold engine or both cold and warm?
What tranny do you have?
Is gas mileage suffering?
Is this a new problem or has it been going on for months?
You may also want to put some fuel line dryer in it to rule out any water in the gas. This is an excellent time of the year for condensation to form in gas tanks, both on the vehicle and at the gas station.




