2001 ZX3, American
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?
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.
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
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.
1. check and clean MAF sensor
2. check EGR valve
3. check the vacuum line from PCV to intake mani for holes and melts
4. check IACV
5. check air intake tube for holes
6. check DPFE see if it's burnt
7. check spark plugs (corrosion, water when cleaning engine), plug wires ends
(corrosion), and coil pack(corrosion)
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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