Power Loss at 50mph

[IAExpy]

I've got a 1st Gen 5.4, and very few mods other than Gotts Mod, muffler delete, and a SCT 93 octane tune (running 93 octane gas) but this problem seemed to be there before any of my mods.

When I'm getting onto the highway, every once in a while I like to re-test my 0-60 time. I seem to have decent power up to 50mph, until it shift's the 4th, and then my power just disappears. Other forums for different cars have suggested checking the fuel filter, but I've replace that and it's still a problem.

Anyone else have this problem, or, more specifically, a solution?

 

[jdan]

Any shaking or sputtering? Running correct size tires?
Scan for codes?

 

[IAExpy]

Any shaking or sputtering? Running correct size tires?
Scan for codes?

No shaking or sputtering, I can hear the air still sucking in strong through the Gotts mod. Tires are stock size, so I don't think that's the problem.

 

[Shadowless127]

4th gear is O/D. Try turning off O/D and see if it helps.

 

[toms89]

I've got a 1st Gen 5.4, and very few mods other than Gotts Mod, muffler delete, and a SCT 93 octane tune (running 93 octane gas) but this problem seemed to be there before any of my mods.

When I'm getting onto the highway, every once in a while I like to re-test my 0-60 time. I seem to have decent power up to 50mph, until it shift's the 4th, and then my power just disappears. Other forums for different cars have suggested checking the fuel filter, but I've replace that and it's still a problem.

Anyone else have this problem, or, more specifically, a solution?

Yep 4th is overdrive. You will not have much power there...the gearing is working against you. It should not be going into 4th wot at 50mph. Are you speaking over 50mph in general, cruising, etc.. or wot.

 

[IAExpy]

Wide Open, I mean it may be closer to 55mph, but it's certainly not 70mph or anything like that.

 

[toms89]

Wide Open, I mean it may be closer to 55mph, but it's certainly not 70mph or anything like that.

3.73's or 3.55's?

Took this from my stock tune file... 3.55 gears, wot shift points. 3.73's would be 5% less mph.

1-2 shift appr. 5,000 rpm 40 mph
2-3 shift appr. 4,600 rpm 64 mph
3-4 shift appr. 4,000 rpm 84 mph

Must be going into 3rd... its possible your feeling the TC lockup in first gear counting it as a shift?!

If it is going into o/d thats your problem.

 

[IAExpy]

I don't know about my gears, I've never changed them and I have no reason to believe the original owner did either, so whatever is stock.

It does seem to help a little bit when I turn overdrive off, but there is still a significant power drop.