1989 Ford Festiva mileage: 125,000. The car has terrible drivability problems, it acts like timing not advancing. It is hard starting, severe engine cut out at almost all rpm and load, and has low power except when over 3500 rpm and full throttle when warm, then runs like normal. Only 22.5 mpg, usually high 30s. I have replaced: coil, ignition wires, cap/rotor, entire distributor with ignition module twice, sparkplugs, fuel pump (helped a little), swapped out carburetor from salvage yard with same mileage (no difference, except idle a little too high now), done propane test for vacuum leaks (none found), replaced many of the vacuum lines on the carburetor (very careful to replace exactly), checked the high altitude compensator but works fine according to Haynes manual, checked/reset timing to 0 TDC, fuel filter, air filter. The problem has slowly gotten worse over course of a year. I cannot drive now due to lack of power and won't rev due to constant cut out. I don't have access to trouble codes. Plugs a little white, running lean I think. Manual transmission, I don't have any hunches left. It's been a very good car since new except for this one problem I cannot figure out. Any help you can give would be appreciated.