1999 tahoe LT 5.7 high mileage stumbles when cold

L O Guvna · Sep 19, 2024

Not sure this is the right section. My tahoe has running issues when first driving. Start engine, put in drive, drive off. Drives like it is low on fuel, air. Engine needs to warm up - short period maybe a minute, and then it drives fine.

Been like this for a while. I've had my regular mechanic fiddle with this. We have changed fuel pump, plugs, cap, rotor, and coil. He also replaced some sensors on the systems for cold start.

Wondering if others have had this. Not a fan of the dealership - i don't mind them giving me an estimate, but those guys will want to restore the car for 10s of thousands of dollars.

Motor, while tired, is in great shape, very strong when running after warmed up.

thanks folks,

Chris
Dallas

Eman85 · Sep 20, 2024

Fiddling, not a professional term.
What is the fuel pressure? Any codes? What are the coolant temp readings on the scan tool when cold,hot?

Marky Dissod · Sep 20, 2024

L O Guvna said:
My tahoe has running issues when first driving. Start engine, put in drive, drive off. Drives like it is low on fuel, air.
Engine needs to warm up - short period maybe a minute, and then it drives fine.
Been like this for a while. I've had my regular mechanic fiddle with this.
We have changed fuel pump, plugs, cap, rotor, and coil. He also replaced some sensors on the systems for cold start.

Wondering if others have had this? Motor, while tired, is in great shape, very strong when running after warmed up.

25 years ago, used to be able to jump right out of bed, ready to kick @$$ before my feet hit the floor. No need for breakfast or coffee. Out the door in 10min or less.
Today, takes at least 60min from the moment my eyes open, to getting out the door - and I prefer 90min.

After 25 years, all your Tahoe wants is ONE EXTRA MINUTE before driving off.
Schidt - as a former cabdriver / chauffeur, I won't put the car in gear for two minutes in the summer, and 4-5min in the winter.

All the above said, I'd not have changed any of the things you had changed,
before changing the fuel filter and the fuel injectors.

L O Guvna · Sep 24, 2024

Eman85 said:
Fiddling, not a professional term.
What is the fuel pressure? Any codes? What are the coolant temp readings on the scan tool when cold,hot?

i'll have the shop run this and get back with you. they ran this before, pressure was down, and replaced the pump. it may be the pump again, so thanks for that. will also get the coolant temps from his tool. thanks Marky

Eman85 · Sep 24, 2024

One thing people forget is the pump can run but at reduced pressure if the connections aren't good.

the 18th letter · Sep 24, 2024

The cheapest option would be to wait the minute for it to warm up before driving off. On my first start up of the day I usually get out and do a walk around after I fire it up.

1999 tahoe LT 5.7 high mileage stumbles when cold

L O Guvna

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Eman85

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Marky Dissod

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L O Guvna

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Eman85

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the 18th letter

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