98 GMC Jimmy. I put on a new water pump last week. Fuel mileage when from
around 18 to 10 mpg. Service engine light has been on a long time before
this. I had AutoZone scan it a while back and was told at that time it was a
O2 sensor. Today I had them scan it again. They said the engine code for the
8th number of the VIN is W.
Codes it has.
P1133 was told this is low fuel pressure regulator.
P0300 was told this is coil pack failure
P0147 was told this is fuel control shifted lean.
Friday I will take a close look to see if any electrical connections, or
vacuum lines were bumped loose from the water pump replacement.
Any other ideas I should do?
Never let AutoZone tell you what the code means. They don't know. They just
know what the code description is.
P0147 indicates something is wrong with the HO2S Heater Circuit. Check
wiring and connections to Bank 1 Sensor 3 heater circuit.
P0300 is a misfire detected so it is possible the coil is bad, but check all
other typical "misfire" components. But, fix the P0147 BEFORE diagnosing the
P1133 relates to the HO2S not working properly, repair the P0147 and this
will most likely go away.
0300 is is random misfire, not a coil pack necessarily. Watch out for AZ's "
help" when they do these scans. 0147 is insufficient switching of one of the
02 sensors, 1133 is heater circuit inop for sensor # 3, which could be after
the cat, you really need a full scan to see what these sensors are doing,
check back on your work make sure nothing is pinched or unplugged, They are
all wet with their code analysis.
Thanks guys. Picked up a new O2, and found I needed a special socket for it.
I changed the one that is behind the cat. It took allot to get it out. I ran
the engine for a while to warm it up and used a torch on it. It came out
hard all the way. When I got it out the treads were GONE. I tried to get the
new one to go it but no luck. Took it to the local muffler shop and they
installed a new port.
I then took it to A Z and had them clear the codes. Drove it for about 5
miles and no service engine light. Fuel mileage is up. Time will tell.
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