I'm not a mechanic, but it sounds like the main relay could be the culprit. It is mostly affected by the heat so it is likely to happen more in hot weather. Hope this helps.
A continuous thumping noise and floor shaking while driving on a 2000 Honda Accord could mean a loose exhaust system. It could also mean a bent frame or a broken spring.
Diagnosis: Engine Won't Start or RunCheck related link below
Ignition switch
My 1998 Accord V6 gets, 25mpg in city driving and 31mpg on the highway at 70mph.
If it varies with driving speed, look for an out-of-round tire. If it vibrates only when braking, you probably have a warped brake rotor.
Remove the muffler
Have your alternator checked
maybe needs gas filter
The car is broken.
wheel bearing?
what causes the light to come on
Heater core is stopped up or thermostat is stuck open.