2004 Tahoe rough start up

[RET423]

I am unsure if you are saying it cranks harder in the morning or it cranks fine but struggles starting.

If it cranks hard only on cold mornings your battery is showing early signs of failure.

If it cranks good but won't start very well try turning your key to "on" but not cranking the starter, wait about 10 seconds with key "on" then engage the starter.

If this makes it start normally it means your fuel pump is bleeding back into the tank overnight, holding the key in the "on" position for a few seconds before cranking gives the pump a chance to build pressure in the fuel system again before you try to light it off.

This is an early warning sign of a dying fuel pump by the way.

 

[bottomline2000]

I have a 2004 z71 Tahoe with the 5.3, I'm having issues with it starting in the morning when it's below 60 Fahrenheit. If I try starting it just turns over, the only way I can get it to start is if I mash the pedal down all the way. It idles rough for about 30 seconds at most. Threw out the day it cranks fine it's just that one cold start after sitting for more than 6 hours at minimum. I just replaced all spark plugs and wires not to long ago, if any of y'all have an idea of what it might be I'd appreciate any help possible!

The cold is making the Intake manifold gasket contract slightly. It's sucking in air that is unmetered. The computer is dumping fuel trying to balance it out. Once the engine heats up the gasket seals and it will run fine. Felpro has a nice thick metal reinforced gasket I highly recommend over the plastic one.

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[justirv]

I have a 2004 z71 Tahoe with the 5.3, I'm having issues with it starting in the morning when it's below 60 Fahrenheit. If I try starting it just turns over, the only way I can get it to start is if I mash the pedal down all the way. It idles rough for about 30 seconds at most. Threw out the day it cranks fine it's just that one cold start after sitting for more than 6 hours at minimum. I just replaced all spark plugs and wires not to long ago, if any of y'all have an idea of what it might be I'd appreciate any help possible!

 

[00chevyHd]

Try cleaning throttle body mass air flow sensor and get the chevron fuel system cleaner

 

[Z28TWITCH]

Did you ever get it figured out? To check if its an intake gasket, once it starts cold, spray some carb cleaner around the base of the gasket, if it changes idle at all, there's the problem. I honestly doubt it though, an intake leak large enough to cause a no start issue isn't going to fix itself after running for a minute.

 

[bottomline2000]

Did you ever get it figured out? To check if its an intake gasket, once it starts cold, spray some carb cleaner around the base of the gasket, if it changes idle at all, there's the problem. I honestly doubt it though, an intake leak large enough to cause a no start issue isn't going to fix itself after running for a minute.

You'd be surprised. Normally the carb spray trick doesn't work. It's hard to get the carb spray to the interior of the intake and if the leak is there the carb spray won't make a difference. Many people have had this issue including myself. My truck ran like it was cammed until it warmed up. The intake gasket was replaced under warranty and it ran fine afterwards..im curious to see what the OP has to say.

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