Hi I`ve got what is seeming like a classic Jimmy 4.3 problem. Hard starting,
rough idle and poor mileage. I initially had the P0300 codeand, as I needed
new wires, replaced them. Th e plugs were new last year with about 15000 Kms
so I havent looked there yet( A job for this weekend). Idle/ acceleration is
better but problem seems intermittent at times. A second read is now showing
P0147(O2 Heater Bank 1 Sensor 3)
Could the miss have caused my O2 sensor to go "bad" or could this code be a
result of the miss and my O2 is reading the rich condition? I dont want to
chase the problem with parts and certainly dont want to change out the O2
and "blow" the new one.
Thanks for the input
1999 Jimmy 4.3 SLS 4x4
Ok So I have codes P0300 and a recent addition of P0147. Service eng light
was on before my wire change but reset after the change and my drive to
work. . I believe my EGR isnt plugged as I can the scan tool to actuate it.
From what I`ve read the rough idle can be caused be plugs, wires, coil pack,
O2, EGR and Cat Convertor. It could also be a bad cylinder but before I get
into eng rebuild, I`m just looking for any advise on which direction to head
first. Should I be looking to replacing the O2 due to the P0147 for the
continuing rough idle or be looking elsewhere? Either way I`ll be checking
my plugs in the morning first.
The P0147 is nothing more than an inoperative heater in the post
cat oxygen sensor. It will not cause a missfire. Verify that
there is proper voltage being supplied to the O2 heater circuit,
if there is, replace the sensor, if there isn't, correct the open
The P0300 is a less than specific indication that one or more
cylinders are miss firing. Could be spark, compression, or fuel
related. A good scan tool will be able to show individual
cylinder miss fire counts which would pin point the exact
cylinder. Given their history, I'd be inclined to suspect the
fuel injectors before anything else.
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