AdsoYo

iTrader: (1)

I wanted to ask for help with this ongoing problem. 14 months ago I posted on this forum about a DTC 64 I experienced which is "passenger side O2 sensor reporting lean exhaust". I never found an answer but tried swapping O2's to see if the problem followed and it did not. It was intermittent so I tolerated it and over the winter I replaced my fuel pump to solve the issue of my car dying on hot days. That's the only modification I've done in these 14 months.

Now, I have a DTC 63 which is "passenger side O2 circuit open". Just like the DTC 64 this one will happen randomly but I haven't had a 64 yet this year. It threw a check engine light once the first time it happened this year about 2-3 weeks ago but hasn't thrown one since and I haven't cleared the code out of the PCM.

The most recent incident was today while I was returning home on the highway. I had my cruise set at 75 mph, about 1900 rpm. All of a sudden, the car starts running rough and the exhaust quiets a little but it maintains its speed fine. Then I can feel the power come back, the exhaust regains its volume, and after a second it goes back to running rough. It did this cycle of running rough, then clearing up, then running rough, then clearing up for a good 5 minutes before clearing up completely. Never got a check engine light.

Here's the numbers I remember from my scanmaster:

Lbl - 160. When car was running well, it was at ~128
rbL - 108. When car was running well, it was at ~128
ceL - 10
O2L - this number was stuck at 445. I thought that was odd since the trouble code was pointing to the right O2. During the cycle I described above, when the car would get its power back, the number would drop to 003, then back to 445 when it ran rough again. When the car was running well it bounced around like it was supposed to.
O2R - bouncing around like normal from 003 - 999 all the time.
IAC - bouncing around as well. From about 80 - 120. When the car was running well it was solid at about 82 or something.
bat - 13.5
egr - the entire trip it quickly bounced from 0-12-0-12-0-12, nothing in between.

It does this during around town driving, too. At stop lights it will cause the idle to drop and run rough. At 35 mph it's real easy to feel the loss of power and sounds like one whole side of the engine isn't getting gas. It feels like it too if I put my foot down. Again, it only last for a few seconds at most then all the power comes back and it may go through the cycle I described above.

Any thoughts? Please share!

englundjd

have you tried changing your o2 sensor's since the computer is throwing a code for them?

RamAir95TA

iTrader: (2)

Check the harness/pigtails to ensure they aren't burned from the exhaust. It's very common.

Ed Wright

iTrader: (1)

You answered your own question. It's a wiring issue. Common problem with vehicles this old. Nobody can tell you where it is. Swapping O2s, then this second DTC tells you it is a wiring problem.

AdsoYo

iTrader: (1)

Thanks guys. I suspected wiring as well, just wanted to get some community input before soldering in new wires.