Fuel cutting out on high gear,

[trav_27]

I have a 98 Expedition with the 4.6 and just reciently I have noticed when going up a grade and it kicks into the highest gear it starts to cut in and out. like its starving for fuel. I just reciently changed the Thottle position sensor and cleaned out the throttle body, also changed the fuel filter. Also put a bottle of Chevron Techron fuel system cleaner in. It runs great no idle problem or problems when just cruising. just when going up a grade it does this. Also I cleaned the Mass air Flow sensor. If anyone can give me some advice, I would appreciate it. Also one other thing. I was greasing the front steering zerk fittings on the passenger side. I called the ford dealer, and they told me that there is only two on the vehicle, on the passenger side steering. I know that I overfilled one of them because grease starting seeping out of the sides of the seal. I also wanted to know if thats bad. Thank you

 

[dyurkosr]

Trav, It sounds like you have an EGR issue. The EGR only comes into play under a load condition. If the valve is stuck closed (which is my guess) it's going to cut power. You can remove the valve (when the engine is cool) and push up on the underside to make sure it is working. While you have it off, look down inside the intake manifold where it is mounted and make sure carbon has not blocked the pasage. if it has, you need to clean it out. BUT..if it's blocked, you may need to remove the intake to do it. you do NOT want to knock that blockage (carbon) down into the intake. Depends how bad it is. On your grease issue, a little should seep out the sides of the seal when you grease it, it's normal. Good luck. Let me know if this works for you. Dan

 

[Little Vinnie]

I would have to suspect an ignition misfire.
A stuck closed EGR valve does not cut power. Well, only if the EGR pressure sensor does not see flow and the computer may retard timing a little to prevent spark knock. Although this timing retard will only be minimal, and not cause "cutting in and out".
If this would be the case, then you would surely set an EGR flow code.
Cutting "in and out", is probably a cylinder specific ignition problem.
Ignition misfires can be counted with a diagnostic scan tool under "mode 6" special test.
A competent automotive shop should easily pick up on this.
Many times it is worth paying for diagnosis rather than guessing at fixes.

Vince