Loss of power

[jwag]

I have a 2003 Expedition with the 5.4 and 74,000 miles and have had it since 2005. Have not had one ounce of trouble with the truck until a month ago. It began to misfire and to eliminate the guessing game I changed all of the plugs and coil packs. Problem solved...so I thought. The misfire is gone, however a new issue has developed. In the am every now and then I will get a little hiccup when I depress the accelarator. Once the truck gets up to operating temp it goes away, but the truck seems to lose power especially in 2nd gear and traveling up an incline. I mean a lot of power. I am not getting any codes to tell me that something is going on. I was wondering if anyone ele is experiencing these issues and was done to correct them ? Thanks

 

[walnuts4x4]

possible vaccum leak somewhere? I had similar problem in mine before... might now be but worth checking out

 

[jwag]

Thank you. I will look over them this evening. Which vacuum line did you have to replace ?

 

[buildingdoc]

The most typical vacuum line to go is the one from the back of the throttle body up against the firewall and goes to the PCV valve on the left valve cover... Sounds like the rubber expands with engine temp and opens up to atmosphere. I would scan for codes after up to temp... You may get some "pending" codes that wont trigger your dash light.

Hope this helps.