this all happened after a new car radio went in have very little power to the car now speedometer stuck on zero drive 4 flashes car barley drives goes maybe 5mph with pedal to the floor what causes this

What is the drive cycle to reset the catalytic converter?

After all this work and still have same issue. Had head refinished and valves done. Still forcing coolant out overflow.

I got a 99 honda civic lx 5 speed i had it for a year n my E-brake never work and i can't find no sign of leaks i have change the master cylinder and still loosing brake fluid i top it off at night n the next morning i wake up i have no brake fluid left i took the drums off n still no leaks could there be a chance that it could leak into my booster wen the car is not running

My Honda 99 civic, used to stall at anytime, and now it will not start? Thought it was the fuel pump or fuel pump relay, replaced my battery cables, is it the ignition switch?

Car will turnover and then die out. Thought it was the fuel pump, but it's good.

I cannot down shift with a step on the accelerator only by use of the shift
lever could this be the shift control solenoid or more serious problem?

So, i bought this 99 Civic VP model about 5 months ago, and had to replace the alternator. It has been ok since then, but recently i have had problems getting it to start. The symptoms now are, when i turn the key to the ignition position, the radio comes on, but seems to turn on and off over and over by itself, and when i press the brake pedal to start the car, it appears that the entire electrical system in the car turns off. I am a little perplexed at this point, and any help or ideas would be appreciated!

I ran it low on fuel and its done it since then i put a used fuel pump in it and its still hard to start in the morning specially when cold but i didn't change fuel rail or injectors need to figure it out tha@nks.

Just have a tune-up , oil change,the works. Don't know what to do.

car is in san francisco, CA