1998 Ford Explorer 5.0L V8 uphill problems

[Nestor1]

Hello I have been experiencing problems with my explorer let's say I'm going 70 MPH in the highway and I aproach a hill my truck does not keep it's speed and goes from 70 to 60 really fast it doesn't matter if a press the accelerator all the way down it will still loose power. I have already replaced the fuel filter as well as regaped my spark plugs but it did not fix the problem I don't know if it has happened to anyone, it has 191xxx miles and no mods have been made just it's normal tune-ups with OEM replacement parts. The worst case that I've have was I was going 80 MPH on the freeway and when I reached the hill half-way it decelerated to 50 MPH I floored it and nothing it downshifted and shifted again. I hope this problem can be resolved thanks for helping!

 

[1998Exp]

Is it just loss of power at high speed, or generally low power? In other words, does it accelerate to 60 just fine, or is it sluggish up to that speed as well? Any codes?
The usual suspect would be the fuel pump, but if it only happens at high speed, perhaps it's ignition. I just replaced my plug wires. If yours are old (say over 50,000 miles), you need to replace them anyway, and because at higher RPMs you need better ignition, they could be the culprit.

Hello I have been experiencing problems with my explorer let's say I'm going 70 MPH in the highway and I aproach a hill my truck does not keep it's speed and goes from 70 to 60 really fast it doesn't matter if a press the accelerator all the way down it will still loose power.

 

[Nestor1]

Its just at any speed if I'm going uphill at low speed it wants to slow down but it doesn't bog 0-60 accelerates just fine but it's just uphill looses power.