cffd175

I have a 2004 silverado 2500hd with the 6.0 gas engine with 116,000 miles. I had a p0300 code come up with a o2 sensor code so i replaced both upstream o2 sensors. code went away for awhile and come back so i replaced the plugs and wires, cleaned the throttle body and mass air flow sensor and code sill come up. then i replaced the crank sensor and the check engine would flash as soon as i hit 2000 rpms while driving. then today i replaced the cam sensor and still the check engine light flashes after 2000 rpms and throws a p0300 code after two drive cycles. also the check engine never flashed before the crank sensor was replaced. any help fixing this problem?

EinST

Welcome to the forum. I think you should seriously consider taking it in for service. You'll have to be extremely lucky to get to the bottom of your problem if you keep throwing parts at it. There are multiple TSBs on your vehicle that address P0300 and flashing CEL, besides.

cffd175

ok thanks. i have a appointment at chevy monday

Tyger

I had the same random misfire code on my 07 Grand Prix, it would get so bad the car would shut off. Took it to my Chevy Dealer and it took 3 days to find a bare spot in the crank position sensor leads which touched against the harmonic balancer causing the short, or misfire condition. "Random" affects any or all 8 cylinders at any time.

cffd175

Freeze Frame Information <table id="freezeFrameTable" style="width:100%; margin:0px 10px 15px 10px;" border="0" cellpadding="0" cellspacing="2"><tbody><tr> <td style="font-weight:bold;">Parameter Description</td> <td style="font-weight:bold;">Value</td> </tr> <tr> <td>DTC for which Freeze Frame was Stored</td> <td>P0300</td> </tr> <tr> <td>Fuel System 1 Status</td> <td>Open Loop</td> </tr> <tr> <td>Fuel System 2 Status</td> <td>Open Loop</td> </tr> <tr> <td>Calculated LOAD Value</td> <td>5.88 %</td> </tr> <tr> <td>Engine Coolant Temp</td> <td>100.40 °F</td> </tr> <tr> <td>Short Term Fuel Trim - Bank 1</td> <td>3.13 %</td> </tr> <tr> <td>Long Term Fuel Trim - Bank 1</td> <td>6.25 %</td> </tr> <tr> <td>Short Term Fuel Trim - Bank 2</td> <td>-0.78 %</td> </tr> <tr> <td>Long Term Fuel Trim - Bank 2</td> <td>6.25 %</td> </tr> <tr> <td>Intake Manifold Absolute Pressure</td> <td>12.44 inHg</td> </tr> <tr> <td>Engine RPM</td> <td>1,008.50 rpm</td> </tr> <tr> <td>Vehicle Speed Sensor</td> <td>21.13 mph</td> </tr> <tr> <td>Air Flow Rate Mass Air Flow Sensor</td> <td>2.23 lb/min</td> </tr> <tr> <td>Absolute Throttle Position</td> <td>22.35 %</td></tr></tbody></table>

EinST

The DTC was declared shortly after getting going. It didn't even have a chance to get into the closed loop. Was there a "crankshaft position system variation learn" procedure done after the CKP sensor was replaced? I'm assuming not since it requires a scan tool that can enable that function. I don't know about what was going on before but the current difficulty can be from the CKP signal variation.

cffd175

no relearn was done. do u think thats the problem?

cffd175

before the crank sensor was changed the check engine light never flashed. it would come and go.

EinST

The flashing CEL means probable catalyst damage, like from too many misfires in too short a time. And, P0300 that early and in open loop can certainly be caused by unlearned CKP sensor signal. You may want to mention that when you take it in.

cffd175

will let them know. hopefully thats the problem.