Just returned from a camping trip to the east coast and had continual "check engine" lites going off and on. Typically only starts after driving a couple hours. We were pulling a small camper as well but I have had this happen in the past when not pulling anything.

When the light starts coming on engine will start to bog down and lose power then all of a sudden come back. If we stop for a little while all is well for a while then starts again. Definetly seems to be related to operating temp. When pulling away from a stop you have to put accelerator to the floor to get moving then all of a sudden it will start running OK again for a little while.

At our second stop at a dealer initially they found only rich and lean codes but no indication of why. Service manager took it for a drive and experienced what it had been doing. He hooked up the analyzer again and saw that the oxegen sensors were both at 1.08 volt and did not change when revving engine. He said he thought it could be the O2 sensors or the computer. He said that they should never be above 1 volt. He felt problem was either the sensors or the computer. They were too booked up in the garage to work on it any further and we did drive home although we experienced the loss of power, poor mileage ect. during the trip.

Does the above diagnosis make sense? Should I get O2 sensors changed or has somebody else been through this that could offer some help. We have been fighting this for 2-3 years and have had no luck in getting it taken care of.



Thanks,

Kevin

 

They are right about the 1V. When I monitor mine, they switch back and forth from about 100mV to 700 mV about every second or so. The post-cat O2 sensors react more slowly. If your O2 sensors are above 1V and did not change either they didn't read them properly or your O2 sensors are most likely bad.

 

Thanks for the feedback. Any idea on cost to replace O2 sensors? Is this something I can do in my garage? Dealer told me that they are often hard to remove.

Kevin

 

Sounds like O2 sensor trouble to me. Mine cost $225 Can. to fix.

 

You can replace the o2 sensors yourself. You will need a special socket, and probably a long handled ratchet, because they can be pretty difficult.

But I have never seen an o2 sensor go bad by reading too high a voltage. All of the failed ones I have seen show no voltage.

A 1 volt signal would be telling the computer to continue to lean out the mixture, which would give you a bad running engine.

I suspect that the problem is either in the computer or wiring. (If indeed the technician measured the correct wire).

Winford