I have an 1989 Escort LX with the single port fuel injection 1.9L motor. Upon startup, the car will initially idle in the 2-3k rpm range before settling down. When driving it, the car stutters, jerks, and hesitates at almost every engine speed except WOT. I´ve replaced the fuel filter, plugs, wires, cap, and rotor. This is a most irratating problem. The car runs and usually doesn´t stall despite this problem. It starts right up and doesn´t seem to lack any power. Any suggestions would be greatly apprecaiated.