I have a 99 Civic Si with 122,XXX miles on it. When im out driving no certain time or temperature the motor seems to lose power really slow down and then kick back up to normal. its no certain RPM's or gear...ive had it happen in all gears. I had a similar problem b4 but that went away...now the car really loses power and loses it for a good amount of time..what could it be? THanks

 

Is the CEL ON? Have you tried retrieving CEL trouble codes from the ECU (see link in my signature)?

 

check for default problems

batteries, alternator, clogged throttle body, fuel lines, fuel pump

 

yeah the CEL is on it says its for the front 02 Sensor but this sensor has been outta wack for awhile and this problem just started up. Would it be one of those problems...alternator, clogged throttle body..etc..even though its not consistent?

 

Im in the process of changing my front 02 Sensor, the guy who had this car b4 me put a universal 02 sensor on it and cut the plug that you plug the 02 Sensor into, so right now im trying to get that plug and splice it back into the wiring, so a new front 02 sensor is on the way.

 

A new CEL trouble code(s) may stored in the ECU, so pull the codes again as you could possibly find a new one. Do you ever notice the lights sometimes fluctuating in intensity at night? Does the charge light on the dash ever turn ON while the engine is running?

Good idea to reinstall the O2 sensor connector. Be sure to solder the wires and insulate them well.

 

No theres no light flickering at night and no charge light either. Its just so strange becuz its very random and does it one day and not the next.

 

1) Pull the CEL codes, and note them. Clear the ECU, and when the CEL turns ON, again retrieve the codes. Troubleshoot only repeated codes.

2) Fix the O2 sensor, which is required for the ECU to determine the optimal air:fuel ratio. This is critical for engine performance and possibly could be the cause of your problem.

 

Alrite thanks. I'll try that n see what I can come up with.