Had the classic symptoms of the sensor going bad, surging and stumbling at cruising speeds. Did the quick fix from the forums just for temporary drivability, and it threw a code. Dealer ordered a new sensor ($31), and I installed it and reset the code. Within 15 miles, the first time I cruised, it threw the code again, and still has all the symptoms of a bad sensor. I tested the EGR valve with a slight vacuum, and it worked fine.
Any thoughts on where to look next?
Steve I think this was one of the recall items. Mine ('01 ZX3) triggered
I had a recall done on it about four years ago. That's when they put on the "new" style sensor, the vertical stacked one mounted on the firewall roughly in line with the EGR valve. It's got over 105,000 miles now.... is there anything else that can cause the sensor to give bad signals and make the EGR surge? I've checked all the vacuum lines, etc.
RR
It also sounds like fuel delivery problem though (fuel pump and fuel filter).
Have you performed all the scheduled maintenance like replacing the fuel filter and PCV?
I battled with this issue and pulled information from all over the net. Here's what I found in summary when you have issues like rough idling. If you also experience that in addition to the cruising, this may help.
The order is random. What I found out online was that many people have issues with DPFE and/or melted vacuum line. In my case, it was a broken rubber elbow hose connecting the throttle body to my AEM intake duct.
Hope this helps and good luck!
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