Sensor Codes

[keithl]

99 with 62,000 miles.

I had an intermittent problem with the car not accelerating properly and at times almost stalling. No CEL though. Car had been working fine for two weeks than CEL
Comes on. I get P1129, P0154, P1127.

Is it reasonable to assume this was causing my accelerating problems? Is my best course of action to replace all the o2 sensors? Anything else I should do or replace?

Also, I always use oem parts but Porsche sensors are $200 a piece. $800 seems kinda steep. Are aftermarket O2 sensors just as good?

Thanks!

[Paul]

Check the O2 sensors wiring first.

[Jager]

Since you have alarms on both sides "lean mixture threshold" I'm thinking vacuum leak. Have you ever replaced your Air Oil Seperator?

[keithl]

Originally Posted by Jager

Since you have alarms on both sides "lean mixture threshold" I'm thinking vacuum leak. Have you ever replaced your Air Oil Seperator?

No I haven't replaced the AOS. I did the Cap "test" and it seem fine, also, the car ran rough with the cap off and clear up with it back on, not getting a lot Of smoke, maybe a little smoke on startup a couple of times a month. So you think it
Could be something other then the O2 sensors? Thanks.

[Topless]

Your car is running rich. It sounds like a possible bad MAF. From Renntech.org:
http://www.renntech.org/forums/topic/7558-p1129-odb-code/

Disconnect the MAF and drive the car. If it runs better, replace the MAF. Your O2 sensors are simply reporting the problem and are probably fine.

[keithl]

Originally Posted by Topless

Your car is running rich. It sounds like a possible bad MAF. From Renntech.org:
http://www.renntech.org/forums/topic/7558-p1129-odb-code/

Disconnect the MAF and drive the car. If it runs better, replace the MAF. Your O2 sensors are simply reporting the problem and are probably fine.

I did clean the sensor, which seemed clean. The problem is the car really has been running fine the past two weeks. I'll disconnect it and see if I can tell a difference.
I appreciate the input and ideas!

[Jager]

When you remove the oil fill cap while the car is running (eninge needs to be warm) the idle will increase a little if your AOS is good. It might idle a little rough but idle RPM's should go up a little. If the idle drops and runs real rough (almost stalls) you have a bad AOS. Was the cap hard to remove due to a lot of vacuum?

[keithl]

Originally Posted by Jager

When you remove the oil fill cap while the car is running (eninge needs to be warm) the idle will increase a little if your AOS is good. It might idle a little rough but idle RPM's should go up a little. If the idle drops and runs real rough (almost stalls) you have a bad AOS. Was the cap hard to remove due to a lot of vacuum?

Cap easy to remove and the RPM's increase, so I guess the AOS is good. Oh well.
Thanks for the suggestion.

[Jager]

Have you performed Topless's suggestion of removing the MAF sensor to see if runs better?

[keithl]

Originally Posted by Jager

Have you performed Topless's suggestion of removing the MAF sensor to see if runs better?

I haven't yet, because right now it seems to be running fine. Im waiting for it to act up again. Intermittent problems are frustrating. Thanks.