Start-Up Problem

[02gmcdenali]

Hello, I have a 2002 GMC Yukon XL Denali. I decided to post this in the standard wheelbase section because it is not specific to a XL. It has 340k miles on it but runs ok once its started. When trying to start the vehicle, it cranks and stutters but doesn't want to fire off. If I give it gas, it starts but still doesn't start the way it should. I tried cleaning the throttle body because it was really dirty. I am thinking my next step is to measure the fuel pressure to see how the fuel pump is doing. I am curious what others thoughts are on this problem? Thanks for any suggestions.

 

[Rivieraracing]

Did this just happen? Did you do any recent work on it?

I'd look at fuel pressure and also plug wires and coil packs!

 

[02gmcdenali]

Bought it this way. Once it's running it is good but I haven't done anything but clean the throttle body.

 

[Rivieraracing]

Might also be cracked intake manifold or bad manifold gasket since it runs like crap at first but gets better when it's warm!

 

[02gmcdenali]

Good point but it runs and idles good after about 5 seconds...lol

 

[02gmcdenali]

Problem fixed! The coolant temp gauge was not working so I decided to replace the coolant temp sensor. After I ordered it I remember stuff I had read about fuel tables and coolant temp and started to think that a new sensor might fix my problem. So I installed it the Yukon runs great now. Thanks for the advice.

 

[comerz1]

Yep when those go bad it goes to a default fuel setting at start up for -40*, WAY too much fuel typically.

 

[Rivieraracing]

Right on man, glad you found the fix and it wasn't a huge deal to get done! Thanks for checking back in with your result, I will for sure log that in the back of my brain for the future!