Rough Starts

[Danny Leblanc]

I was doing some steep hill climbs last week and the X preformed like a champ. A few days ago my starting problem started.

When I start the truck it stumbles alittle then idles good. It only does this after sitting a few hours. There is no gas fumes or fuel leaks. It sort of sounds like its loosing its prime.

Another thing I noticed is when I turn the key to the run position (not the start position) I can not hear the fuel pump priming but it idles good once it starts.

Anyone have an idea?

Thanks
Danny

 

[Danny Leblanc]

Anyone?

 

[mikehawk]

Are you sure it's not a vacuum leak?

 

[Danny Leblanc]

Im not sure... i'm used to working on 4.6L V8s. How would I check for a vacum leak?

 

[mikehawk]

Pop the hood with the engine running and listen for hissing. Make sure all the rubber lines coming off the vacuum tree on the back right side of the manifold are in good shape.

I finally tracked down a vacuum leak that was giving me problems for a while. Turns out that the hard line that runs behind the engine, down and back under the firewall is a vacuum line for the transmission valve body, and there is a short segment of rubber hose underneath the truck. Might want to check that one out if you've done some off roading and ran some **** over. Could have gotten hung up on something.

 

[unclemeat]

I would also check the electrical plug connection to the IAC and MAF ect.

 

[Danny Leblanc]

I checked for vacum leak and can not find one. I also checked my IAC and MAF.
Today I got my friend to go in the truck while I laid under the gas tank. When you place the key in the run position, the fuel pump should prime right? There was no noise at all. When he placed the key in the start position, the fuel pump started to prime.

What would cause this problem?

Thanks for the help.

 

[unclemeat]

You can replace the fuel pump relay and then try it again. They are cheap and Gen. I Xs are notorious for the fuel pump relay going bad.