Looking for Assitance with Power Issue?

[DawsonJB]

Dont know how to start this but I guess an initial question would be, What should I check as far as fixing performance issues, I just recently Replaced my Sway Bar Bushings, Front Shocks, and Inner/Outer Tie Rods, However at the date of this post I'm still her lol, However I drove from Marysville, WA to Kelowna, BC to visit my Grandpa, the Ford did amazing only having to fill up twice along the entire route one at River Rock and another at Elk Hart, However one thing I was noticing is that when I got to an Incline it would struggle a little bit get get up the hill and if I had to slow down the acceleration was absolutely terrible, Hit some construction traffic where traffic slowed to an 11mph or less which was for about 3 miles in length once I got through it, It opened way back up to 2 lanes and I pushed my foot the floor, and it took about 7 min (probably more estimating) in total for my Ford to accelerate from 14mph to 75mph (~120km/h), which seems a little excessive to me.

I've been considering upgrading my Transmission to one of the XP(Xtreme Performance) 5R55E Transmissions where they have the upgraded Valve Bodies and such and sending back my tranny as a core, However wondering if there is any other changes I should make to it, I read some forums on this page talking about Checking the slack in the Throttle Cable which i will do tomorrow while I'm here in Canada, But I've also been pondering swapping my factory airbox over to a K&N Cold Air Intake with the MAF Port on the main Aluminum Pipe to increase air flow, wondering if there is any other recommendations that I should to or repairs I should check to help increase my power I know this motor is Low HP, but I absolutely do not believe that I'm getting the HP this motor is rated for.

 

[toypaseo]

When was the last fuel filter replacement?

 

[wollimann]

any other recommendations that I should to or repairs I should check

What about transmission fluid level and transmission oil temperature?
The 5R55E has a thermal bypass valve inside the valve body which could be out of order, many transmissions
died of a heat problem.

Throttle cable slack could fixed with a ziptie at the end of the cable (pedal side).

In my eyes the K&N stuff is not worth the money, no "performance" feeling.

Better investigate money in inspection and good materials. Have an ear on timing chains (if sohc)
and a look at fuel pressure.

 

[V8]

Is the transmission slipping, or what information do you have that leads you to the transmission being bad? In addition to the question about the last trans service, I'd like to add if you have any codes from the ECM to lead you to your conclusion. There are a large number of things that can rob you of power, the fuel filter being one of them for example.

 

[J_C]

Welcome to the forum!

When you have poor acceleration, is your tachometer showing appropriately higher RPM than at steady cruise speed? If not then I would look at engine issues rather than transmission. In addition to checking fuel pressure, I'd hook up a scan tool that's capable of live data, to check codes and see if you have good long term fuel trims and no misfires, and what % throttle it shows when accelerating.

Does it burn oil? Any chance your cat is clogged? A shop could check your pre- and post- cat exhaust pressure.

I assume you don't just have a clogged air filter nor a rodent that built up a winter stash of food in the intake. Otherwise it's unlikely to make much difference to swap in a so-called performance intake or filter.

Is it the 4.0L OHV engine and how many miles on it? If nothing else pans out, do a compression test.