matrix11229

I bought my 97 Maxima 3 weeks ago with Check Engine Light On. I had it diagnosed and found that one of the front O2 sensors and Knock Engine sensor have to be changed. The mechanic turned my CEL off using the computer and told me just to drive with it and see if it comes back on.

Any way my car did 12 MPG in the city, so I ordered knock sensor and both front O2 sensors (Bosch universals) on Ebay from the same seller that some members here bought from.

I replaced the sensors (cel didn't come back on yet) and I felt a huge improvement in power and the car stopped shaking when it stands with shifter on D.

On Thursday I went to Staten Island driving 60-70 MPH while it was raining and water spilled on the engine from underneath, and suddenly the CEL turned on and I think I felt like the car got less power again.

Then, on Friday night I went to St. Island again (it's 12 miles away) and back to Brooklyn and then back to St.Island and back home to Brooklyn and suddenly the CEL turned off !

I have no idea what's going on. May be because I went over some deep water, it spilled on the engine and somehow got on the o2 sensors ??

Did anyone have the same issue ?

whitegold

iTrader: (1)

You can pull the codes whent he CEL turned on. See if you have any ghost codes. But if the ECU decided whatever was broken fixed itself itll turn the light off.

dko

iTrader: (7)

it happens. if the light stays on after a few starts, run the codes and go from there.

matrix11229

How do I check for ghost codes ? By turning the ecu selector ? Even if my CEL is off will it blink ?

dko

iTrader: (7)

yeah. there are certain codes that will not illuminate the CEL but can be checked using the procedure shown in the stickies. the knock sensor code, for example.

matrix11229

I don't think I had any other codes besides the front O2 sensor and knock sensor because my car was computer diagnosed for error codes.

The only thing that bothers me is that CEL turned on while driving in rainy weather and then turned off when it was dry weather.

So I wonder if I have any holes in the manifolds or something where water can get in ?

I heard that if the O2 sensors are clogged/stained which can trigger the CEL, you should drive on high speed on the highway and the O2 sensors can clean themselves.

So probably that's what happen to me , after fast driving the CEL turned off,
the only thing is that both of my front O2 sensors are new.

Is this possible that I have some kind of mechanical problem which clogged the new O2 sensor/s ?

matrix11229

It's already 5 days since the CEL turned off and everything feels fine. Do you think it's a good idea to replace the back O2 sensor ? Will it improve the gas mileage ? I can buy Bosch universal for $28 shipped.
(the car has 189,000 miles and I think the back O2 sensor was never replaced).

samito

iTrader: (1)

best thing to do is have the computer scaned and see if there is any codes . the o2s are in the exhaust they can't get wet