cars lights/electrical going crazy
 

hey,

so if anyone can help me out id really appreciate it.

Recently my check engine light came on and I pulled 4 codes from it:

1. P0135 Sensor heater circuit malfunction [bank 1 sensor 1]

2. P0141 Sensor heater circuit malfunction [bank 1 sensor 2].

3. P0501 Vehicle Speed Sensor

4. P0420 Catalyst System Efficiency Below Threshold (bank1)

and they all came on at the same time. 2 days after the car started acting up where all the lights (outside/inside) would be pulsating and the speedometer stopped working as well. When I would be driving the car it would be jerking and as if its going to die but I would just keep the RPM's high and pop it in neutral when I came to a light and keep the RPM up.

Checked the battery and it read 12v when the car was on and same thing at the alternator.

But if it was the alternator that went and the battery wasn't holding any juice then wouldn't the car just die? why would it keep running if I kept giving it gas?

Has anyone come across the same problem? and I didn't change anything in the car, it just started doing it one day.

Thanks

by the way its a 98 honda civic sedan (auto).

had that same problem on a 1998 sedan too. turned out to be a wire rubbing behind the intake manifold. check that out.

check your grounds. also do you hear any rattle from under the car? the cat may be plugged giving you problems with the first 2 sensors. and being an auto maybe it's slipping because the wheel speed and engine speed are not matching up the way they should because your blocked cat blocking exhaust from leaving the engine. see if you can get the primary o2 senor (closest to the engine) out and if that changes anything it's your cat. otherwise I'd say it's electrical.

side note, are you running old gas and have you ever changed the fuel filter? less likely cause is maybe your running too rich/lean and that is screwing up the readings on the sensors. not sure how this could effect your speedo though.