Difficult Starting When Warm

[Conner2]

I have an '03 Silverado 5.3 with about 86,000 miles on it. Recently, I have had issues with it starting after it has been sitting for 2 -3 hours.

 

It starts fine in the morning (after sitting for about 10 hours), and if I go to lunch (after about 6.5 hours) I don't have any issue, but if I drive it at lunch, it is hard to start at the end of the day. (about 2.5 hours later)

 

If I turn the key, and wait a few seconds, it seems to start better, but it still idles rough for the first few minutes.

 

No check engine light, I ran 2 bottles of injector cleaner through 2 tanks of gas. (No help)

 

Any suggestions on what to look for?

 

 

J.Conner2

[[email protected]]

I have an '03 Silverado 5.3 with about 86,000 miles on it. Recently, I have had issues with it starting after it has been sitting for 2 -3 hours.

 

It starts fine in the morning (after sitting for about 10 hours), and if I go to lunch (after about 6.5 hours) I don't have any issue, but if I drive it at lunch, it is hard to start at the end of the day. (about 2.5 hours later)

 

If I turn the key, and wait a few seconds, it seems to start better, but it still idles rough for the first few minutes.

 

No check engine light, I ran 2 bottles of injector cleaner through 2 tanks of gas. (No help)

 

Any suggestions on what to look for?

 

 

J.Conner2

 

Possibly your fuel regulator, fuel pump, or injectors. When mine did that it was the CTP sensor.

[Jae77]

I had this same problem when my Fuel pump started to go ..

i'm however not a mechanic.. but i have run into a similar problem

i remeber keeping my tank topped up helped the pump last a little longer as it was an in the tank pump on my honda

[ColoradoSkiCountry]

Yup. Fuel Pump is going out and or the Fuel Pressure Regulator. VERY common problem on the GMT-800s. Had the same issue on my 99, turned out to be the Fuel Pump going ka-blooey.

[gmtech121]

03 is old style.. pull the vacuum hose off the fuel press reg. Start the truck... let it run a min... shut it down... look for fuel leaking out of the port.

[Conner2]

03 is old style.. pull the vacuum hose off the fuel press reg. Start the truck... let it run a min... shut it down... look for fuel leaking out of the port.

 

 

What will that tell me?

[txab]

03 is old style.. pull the vacuum hose off the fuel press reg. Start the truck... let it run a min... shut it down... look for fuel leaking out of the port.

 

 

What will that tell me?

 

 

That the pressure regulator is bad

[Bob_fromLA]

Same issue I had with my 2001 8.1 2500HD. A real clue for the regulator leaking issue is that the truck will start when warm, if the throttle is opened and then it runs rough for a few seconds. At least on mine, the leaking could be compensated for by the emissions system once running. I did the suggested check and note that just putting the ignition in run position did not show the leak, I actually had to start the engine (I blocked the vac line).

 

I'm apparently also luck on the 8.1 that the regulator is right on top, so about 15 minutes for everything. I note that Rock Auto has a selection of regulators at good prices and fast delivery.

[Debo511]

 

 

 

03 is old style.. pull the vacuum hose off the fuel press reg. Start the truck... let it run a min... shut it down... look for fuel leaking out of the port.

What will that tell me? That the pressure regulator is bad Sounds like a bad regulator to me, ussually you can just pull the hose and see wetness and a fuel smell if it is bad.