2005 Sierra Cold Start Issues

Aggie96 · June 1, 2009

Hey all...I have a 2005 Sierra Crew Z71 with the 5.3 liter engine. I just recently started having some cold start issues with it. It only happens in the mornings when the truck has been sitting. What happens is when I initially start it, the RPM's drop real low and starts acting like it's gonna stall on me and then it levels out and idles normally. It doesn't do it any other time of the day, just in the mornings. I'm thinking it might be the mass airflow sensor, ditrty injectors. Needless to say the factory warranty already expired!

Any suggestions??

bill190 · June 1, 2009

What you would need to do is "test" various sensors to the engine computer as part of troubleshooting as outlined in a GM factory service manual set for your specific vehicle(order from dealer).

Testing can mostly be done with a multimeter.

AINTNOFORD · June 1, 2009

I have the same issue with my 2009 Denali. They told me that this area received some gas that seperated after shipment. What ever that means. Anyway I have put a couple of bottles of dry gas into my tank to absorb any water and it seems to have improved a little. They have replaced the MAF already and will be replacing some fuel module. Good luck.

ColoradoSkiCountry · June 2, 2009

On an 05 depending on how many miles you have, I would suspect a bad Fuel Pump (located INSIDE the gas tank, replace the whole fuel sending module, it will fix your faulty gas guage, and take care of replacing the fuel filter which is also inside of the tank) AND/OR you may have a bad Fuel Pressure Regulator, which is located in the engine compartment. Go ahead and have your fuel system checked, make sure good pressure, and such. May have to leave the truck at the mechanic overnight so that they can watch the pressure right at the moment of start up.

Try this as well: In the morning, turn the key to run (not start) 2-3 times (wait 2-3 seconds before turning the key off then back to run, then off, then run, then off then start.. see if the truck starts up well and idles well after following that procedure. That might help determine if you have a fuel pressure issue.

Cheers,

Ryan

98 Z71 SLT · June 3, 2009

Hang on...bad info above post

Fuel pressure regulator is IN THE TANK on 04 and Newer ...

You have a "return-less" style fuel system. Sorta like "fuel on demand"

How can you tell??

Look at your intake area. If you have 2 fuel lines next to each other (feed and return) then you have the older style fuel system, used from 1988-2003

If you only have one fuel line, you have a return-less system. 2004-current.

BTW..your FUEL PRESSURE is.......................at key on? .............................engine idling ??