After Civic washed the throttle, the throttle became heavier.

Judging from the phenomenon, it is still a throttle problem. It may be that the sludge and dust were not cleaned up last time. The most thorough method is disassembly and washing, although the process requirements are more complicated, but the effect is better. Pay more attention to cleaning the air filter at ordinary times and try to reduce the time of driving at low speed.