I have a 2001 Focus with the 2.0L SPI engine, 5spd manual
transmission, about 75K miles. Plugs about three months old, fuel filter
The Ford dealer I bought it from had a bad tendency to take at least
two visits to fix one problem. Either stupid or cunning, your choice...
When accelerating and up shifting, it occasionally drops a cylinder
or two, then it smooths out. What aggravates it is being a gear too high
for the speed it's at. Like 20MPH in third. Then it stumbles a few
seconds before getting enough speed to get out of whatever combination
that causes the problem. Bucks a little.
This was happening in temperatures over 60 degrees and now it's down
in the 20s.