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2009 Silverado 5.3 rough idle

Ashtonross
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Ashtonross Enthusiast

Ashtonross

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Posted (edited)

Please help I recently purchased this truck after my last was totaled it ran perfect for two weeks an then randomly started idling really rough wanting to die out. I’ve replaced the fuel pump, spark plugs, starter, positive and negative wires from battery, new MAP sensor an the oil pressure sensor. It’s throwing po106 po507 po573 po2119 codes and when I clear them the truck won’t start. But it will crank up with starting fluid I checked fuel pressure an it’s at 65-70psi on startup please help

Edited by Ashtonross
Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
Posted
38 minutes ago, Ashtonross said:

Please help I recently purchased this truck after my last was totaled it ran perfect for two weeks an then randomly started idling really rough wanting to die out. I’ve replaced the fuel pump, spark plugs, starter, positive and negative wires from battery, new MAP sensor an the oil pressure sensor. It’s throwing po106 po507 po573 po2119 codes and when I clear them the truck won’t start. But it will crank up with starting fluid I checked fuel pressure an it’s at 65-70psi on startup please help

 

 

I would say that there is some sort of problem with your vehicle.

 

Replacing random parts will only make the problem worse, not better.

 

Every part that you replace might cause more problems. For instance, if your old fuel pump was working fine, and you replace it with a brand new (but defective) fuel pump - then you have added more problems to the situation, yet you completely discount the fuel pump as an issue, because its brand new. Now you have 2 major problems, and have spend time and money - which only results in a much more difficult diagnosis.

 

If you want to replace the fuel pump, make sure its actually bad first.

 

Also, you can spend $1,000 and countless hours replacing random parts, when a diagnostic only costs $100 and takes an hour.

 

Its all all about the basics:

 

Fuel

Air

Timing

Spark

Compression

Fuel/air ratio

 

Which one is not working properly?

 

  • Like 1
Ashtonross Enthusiast

Ashtonross

Posted
  • Author
Posted

I did run a fuel pressure test and it was below 40psi so I replaced the pump now it reads 60 but I still have the same issue. It runs just fine on the road but when coasting or idle it wants to die. I replaced all spark plugs today I haven’t checked all coil packs yet though. The sensors I replaced were all throwing codes to be replaced but replacing them didn’t take the codes away

Ashtonross Enthusiast

Ashtonross

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  • Author
Posted (edited)

I bought it off a guy who said he was the only owner it has 96k miles and has been airbagged some of the wiring under the steering column has been messed with but I don’t think any of it is damaged it also is missing the parking brake for some reason

Edited by Ashtonross
Ashtonross Enthusiast

Ashtonross

Posted
  • Author
Posted
27 minutes ago, Supreme Pizza said:

 

 

I would say that there is some sort of problem with your vehicle.

 

Replacing random parts will only make the problem worse, not better.

 

Every part that you replace might cause more problems. For instance, if your old fuel pump was working fine, and you replace it with a brand new (but defective) fuel pump - then you have added more problems to the situation, yet you completely discount the fuel pump as an issue, because its brand new. Now you have 2 major problems, and have spend time and money - which only results in a much more difficult diagnosis.

 

If you want to replace the fuel pump, make sure its actually bad first.

 

Also, you can spend $1,000 and countless hours replacing random parts, when a diagnostic only costs $100 and takes an hour.

 

Its all all about the basics:

 

Fuel

Air

Timing

Spark

Compression

Fuel/air ratio

 

Which one is not working properly?

 

If I was having some sort of spark issue I would think it would give a misfire code an I haven’t got one. After I check for a vacuum leak tomorrow I’m not sure what else it could be thanks for your time

Ashtonross Enthusiast

Ashtonross

Posted
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Posted
1 minute ago, Supreme Pizza said:

Ya, checking for a vacuum leak couldn't hurt. I used starting fluid for the test, but that's just me.

 

Could be water in the fuel?

 

Clogged air filter?

 

 

 

1 minute ago, Supreme Pizza said:

Ya, checking for a vacuum leak couldn't hurt. I used starting fluid for the test, but that's just me.

 

Could be water in the fuel?

 

Clogged air filter?

 

 

When I changed the tank I drained all the fuel out an put new back in an checked the tank to make sure it was clean. My air filter has been cleaned but it does have a small burn with a pen hole in it from hiting my header. I checked for a vaccum leak with starting fluid today but got nothing so I’m trying with a smoke tester tomorrow 

Ashtonross Enthusiast

Ashtonross

Posted
  • Author
Posted
17 minutes ago, Supreme Pizza said:

Might try disconnecting the Mass Airflow Sensor, to see if that helps.

Alright I’ll give that a try thanks

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

That won't help any. The codes don't point towards the MAF sensor at all.

 

The codes are MAP and throttle related. Check the harness for damage. Ideally a scan tool would be used to watch the parameters to see what is going on.

  • Like 1
swathdiver Senior Enthusiast

swathdiver

Posted
Posted

I responded to you in the Silverado/Sierra forum.  All those codes seem point to an improperly functioning throttle plate or a bad ECM.  Whether the throttle plate is dirty, bound up, or jammed by debris, you'll have to check out.

 

If you plan to keep this, get a Tech-2 and a subscription to the shop manual and trouble shooting guide at AllDataDIY or buy a pdf copy off Ebay from SeriousCTBuyer.

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