Engine Power Loss (Momentarily) when making right turn

[Chris Wallace]

Hi - New to Forum.

I have 99 Expedition XLT 4x4 w/ 5.4L. Have been experiencing this issue for several years without figuring it out. I don't drive it much - maybe 3000 miles per year. It is used primarily for trailering.

This started when I took a road trip out west w/ trailer. When making sharp and even gradual right turns, I have a loss of engine power, as if it is not getting fuel. This happens most times, so as an example, if I make a right turn, give it gas it goes, but then I lose engine power for a moment (1/2 - 1 sec). Then it recovers and goes as normal. Every time I think I fix it, it still persists. Here is what I have done over the course of the last few years (this is probably not a complete list):

1. Spark plug replacement and Coil pack replacement
2. Replaced fuel pickup/pump
3. Replaced fuel filter
4. Replaced Fuel pressure regulator on engine fuel rail

I have checked and rechecked all fuses, wiring connections. I have also checked in wheel wells to see if anything is happening that is causing a restriction or shorted wires = all good. Fuel pressure is good. No codes thrown. No engine light. Electrical power is not affected.

I do have an right side exhaust manifold leak - the notorious warped manifold syndrome that most F150/Expeditions experience (this is second manifold that was replaced by dealer 8/9 years ago. Not sure if I am getting air sucked back into the exhaust that is causing this??

I also had a spark plug ejection, that was tapped out and had an insert sleeve installed 4 1/2 years ago.

 

[1955moose]

Your exaust leak could definitely cause your stumble. Years back when cars ran with a richer mixture, an exaust leak was no biggie. But these days our Suvs look like a human flatlining on a scope. Amazing they run as strong as they do. Are you throwing any lean code?

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[Chris Wallace]

No codes thrown! Last codes thrown were for misfire related to coils.

 

[Flexpedition]

While parked in the driveway idling, does a sharp right turn substantially bog the engine down moreso than an equal left turn?

 

[1955moose]

Chris I think flex is thinking your transfer case may be engaging. Or a binding of the CV shaft. Do your hear any clicking when you turn and accelerate?

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[Chris Wallace]

I will check turning wheels while idle, but I do not believe it bogs down while stationary and turning in either direction. Condition is only when driving.

No clicking noises from front drive axles.

The loss of power is acting like loss of fuel for an instant and only when at speed. Slow turns has no affect.

Come to think of it, I always back into my parking space at the office and always with wheels turned hard right. Occasionally I feel a jerking like my suspension is making adjustments (it has air ride system.)

 

[Club Expo]

Mine will shut off for a half second just like this. after owning it for 3 years I have noticed it only does it when I have a quarter tank or less like as if the fuel is slashing or something like that, hard to explain but I haven't figured mine out either! If I come to a hard stop then gas it it will do that every time.

 

[Chris Wallace]

This happens no matter how much gas in in tank.

I checked turning wheels while idle and in gear (with brake applied). No change in engine performance.

Loss of power happened twice this morning. Both times when accelerating into or after the right turn. Sometimes it does it in the turn, other it happens just after the turn is complete.

I'm going to replace exhaust manifold - but dreading the nasty stud removal - i know two rear studs are non-existing - the rest look dicey!!

 

[1955moose]

If funds allow, maybe pay someone that's good with exaust, and in particular broken bolts. A broken stud is no picnic, especially when theirs 0 room to work. Be sure to have an angle drill, and all the tools/removers you may need. That and spray the hell out of every nut/stud hours before you tackle job.

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[lpburke86]

Do you have the plastic, or aluminium intake manifold?

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[Chris Wallace]

Aluminum

 

[plumcolr]

You most likely have a wiring issue where a right turn allows a wire or harness to touch metal and ground out. Most likely it is under the hood, either along the left fender or dressed along the top of the engine. Other possibilities include along a frame rail, example the fuel pump control unit. Look very closely where wire or harness is dressed against metal. Check by the steering gear and shaft, too.

 

[rjdelp7]

Pull electric clutch fuse, 102. You drive train may be binding up, due to stupid Auto4wd. Ford should of had a 2wd option,for dry pavement. I always disable mine, in summer months. Check your diff fluid level. It may be low and engaging in turns.

 

[Chris Wallace]

Did some work on the Expedition this past weekend. Changed out Pass side drive axle & Hub. Test drove and still getting loss of power on sharp turns - actually happens after straightening wheel after the turn. I did not inspect wires - ran out of steam.

Pulled fuse 104 - 4WD maxi-fuse - no difference with power, but I did notice some noises go away.

 

[Bain64]

Pulled fuse 104 - 4WD maxi-fuse - no difference with power, but I did notice some noises go away.

Noises like what? 4WD engage/disengage?

 

[Chris Wallace]

Bain64 - I'm going to start a new thread about the 4WD issue in the correct spot - either transfer case going or differential - likely transfer case. when in A4WD i get a a quiet rotational sound - I thought it was as a result of cv axle shaft slightly bent. When putting into 4WD High - i get a lot more rotational noise - not grinding but like it is struggling and the front axle becomes very noisy whirring sound. Get some lurching almost like putting in 4WD Low. I'm thinking to take to Trans shop to get opinion.

My loss of power has not been resolved. Thinking of replacing Camshaft position sensor - it's cheap and it cant hurt to replace. Will also check for bare wires while at it.

 

[1955moose]

This might be kinda out there, but a loss of power after banking a corner sounds like fuel sloshing/starving like race cars sometimes get. It's possible the new pump is bad, but your getting the same symptoms as before. Did you ever fix your exaust leak? If not your SUVs trying to compensate for the lean condition. And this could drag on forever.

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[01ExpeditionXLT]

I have experienced this exact same problem but with an 03 Crown Victoria. Both vehicles have a 4.6L and 4R75W trans. My Expedition has never exhibited this behavior in the 17 yrs I have owned it and my Crown Vic only started doing it after a new fuel pump was installed.

 

[Jdeezy06expo]

I will check turning wheels while idle, but I do not believe it bogs down while stationary and turning in either direction. Condition is only when driving.

No clicking noises from front drive axles.

The loss of power is acting like loss of fuel for an instant and only when at speed. Slow turns has no affect.

Come to think of it, I always back into my parking space at the office and always with wheels turned hard right. Occasionally I feel a jerking like my suspension is making adjustments (it has air ride system.)

Hey,not sure If you ever figured your issue with loss of power during sharp turn but I figured mine out, a faulty steering wheel position sensor..