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P0300 Code only in 6th gear? Slight stumble.

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Old 06-16-2013, 10:50 AM
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Default P0300 Code only in 6th gear? Slight stumble.

When I shift my 01 SS into 6th gear at under 60mph the car stumbles and the check engine light starts flashing. It stores the P0300 code. Runs fine otherwise except I have lost 2mpg's, so somthing is up! Anyone ever have this problem???

-Dan
Old 06-19-2013, 06:47 AM
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still searching!
Old 06-20-2013, 07:45 PM
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How many miles on the car? Ever changed the plugs and wires?
Old 06-22-2013, 10:22 AM
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In 6th gear under 60 is a lot of load for low end on the engine. Did the misfire tell you a cylinder #? I agree with checking plugs/wires, and depending on mileage you may also be looking at a coil.
Old 06-22-2013, 12:30 PM
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http://www.obd-codes.com/p0300

Like GMRL suggested, check the plugs and wires and see where you're at.
Old 06-23-2013, 05:41 PM
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I just did all the plugs and wires, still a stumble. Car has 89K on it. Ordered
O2's but not installed yet....
Old 06-23-2013, 05:47 PM
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It only happens under a load at less than 1500rpms. hoping its the 02's, they ARE 12 years old now.
Old 06-23-2013, 05:56 PM
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So you have NO effects above 1500 rpm? And no effects at idle? That is strange indeed. Makes me wonder if the idle circuitry is having an issue, or maybe the throttle system itself? Do you have access to a scanner (HpTuners, etc)? I would want to see the voltages on TPS from closed to open, then go through IAC stepper motor changes. I've seen strange things with TPS being bad in small ranges, which can wreak havoc on the fueling and ignition.
Old 06-25-2013, 07:34 PM
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Checked the throttle body/MAF, both where soaked with oil. Anyone have an idea where the oil is coming from...may be affectiong thr MAF??? From what I feel while driving it is there is no problems over 1500. Idle MAY be a smidge choppy, but hard to tell. I changed all of the 02's and the problem persists. No scanner at the moment.
Old 06-26-2013, 12:26 AM
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Originally Posted by 01LS6SS
Checked the throttle body/MAF, both where soaked with oil. Anyone have an idea where the oil is coming from...may be affectiong thr MAF??? From what I feel while driving it is there is no problems over 1500. Idle MAY be a smidge choppy, but hard to tell. I changed all of the 02's and the problem persists. No scanner at the moment.
If you have an aftermarket air filter that could be where the oil is coming from. It could cause your problem but not likely. Id be looking towards testing coils now.
Old 06-29-2013, 09:53 AM
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I took out the SLP MAF sensor and put the stock one back in, as well as a new PCV. Still the same problems and code(0300). Any suggestions as to how to correctly test the coils to find a bad one instead of replacing them all?
Old 07-07-2013, 11:43 AM
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Basic coil test is to go across the primary windings and do a resistance check. You should get a near short/ 0 ohms. Then do a primary to secondary check (PCM/little wires in to the output spark plug wire hole), and make sure each reads open or very high ohms.



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