2000lsv8 acceleration problems

JustALs

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yo guys new problem, no missfire and no codes, cleaned the injectors , havent checked my fuel filter as I put a new one just few months ago.
can this be cause by a weak fuel pump? lately when starting the car it misses a bit but then runs like a champ, even tho it did this for months it only started to act wierd on acceleration yesterday

when cruising at 100kmh and I punch it the rpms jump a little like 4k and it shudders like its cutting.
kind of feels like the advancetrac is kicking in but its not ,,I always drive with it turned off and its not flashing when it happens. my alignment is terribly off right now as I replaced the front steering knuckles,
I was thinking a broken axle on one side but I dont even think it would drive at all
thx
 

joegr

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Yes, a bad fuel pump might cause similar symptoms.
It could be that the exhaust is getting restricted by the catalytic converters getting clogged from whatever missing has been going on.
Also, I wouldn't 100% count AdvanceTrac out. You can't turn it 100% off. (Jaguar has a way to do this, but AFAIK, the LS never got that feature.)
No, you would have no traction with a broken axle.
 

JustALs

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thanks joe apretiate it , I just figured the problem lol , I had like 35kms left in the tank , filled it earlier and everything is good now. it never did that before even when I was low in gas it so it has to be a weak fuel pump aswell
 

JustALs

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I was wrong it went okay for awhile but then did that thing again.. I did a reset with Forscan for the transmission tables and was probably for the KAM too, after doing that it would go WOT just fine then after a bit of driving it will do it again.. Also Forscan tells me that my Fuel Rail Pressure is 47-Psi at idle, is this good or too low
thx
 

JustALs

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when i punch it 0 to 100 is good no tranny slip and nice shifts but after 100 it does that thing hard to describe feels like its tc is kicking in and choking, the rpm slowly goes up while doing so. just checked fuel rail pressure at WOT ane reads 39psi
ill try cleaning my MAF and check the tps afterwards and if nothing checks out ill check the tranny fluid
no exhaust restriction from cat cause its gutted
 
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JustALs

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Now forscan detected a MAF code, just cleaned it. a day after I got bank 1 - bank 2 LEAN. but fuel pressure drops on acceleration or wot so I will change my fuel filter before buying a new pump
what do u guys think?
thx
 

joegr

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Fuel pressure will vary with demand. As long as it does not fall out of the normal range, it is okay. The PCM compensates by leaving the injectors open longer. The returnless fuel system pressure is not regulated nearly as exactly as the return type systems did.
 

feeninpeece

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Pull the fuse for abs/tcs to completely disable it. Also firms up your steering wheel as it disables the speed variable power steering as well. feels good.
 

LSV8FAN

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when i punch it 0 to 100 is good no tranny slip and nice shifts but after 100 it does that thing hard to describe feels like its tc is kicking in and choking, the rpm slowly goes up while doing so. just checked fuel rail pressure at WOT ane reads 39psi
ill try cleaning my MAF and check the tps afterwards and if nothing checks out ill check the tranny fluid
no exhaust restriction from cat cause its gutted

Nothing mentioned about coils. My experience with my 2005 LS V8 is that when accelerating hard from cruising at 50-55 mph, the car will start jerking; that's my signal to have the coils checked and replaced even though there are no trouble codes.
 

04_Sport_LS

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Pull the fuse for abs/tcs to completely disable it. Also firms up your steering wheel as it disables the speed variable power steering as well. feels good.

Not sure that's a good idea. Most LS drivers don't realize how well the ABS/TCS works... until they don't have it.

Definitely asking for an accident at that point.

Might be wrong... but thought the VPS only worked at low speed... such as in parking lots and what not. (shrug)
 

joegr

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Might be wrong... but thought the VPS only worked at low speed... such as in parking lots and what not. (shrug)
Steering boost is minimized at high speeds and maximized at low speeds. If for some weird reason you want the steering to feel heavy all the time, then pull the fuse.
 

clubairth

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You don't want the PS in high effort all the time. I know as I had a very strange FEM failure in my 2003 LS V-8 Sport. It caused the PS to stay in highway mode 100% of the time. Hard to steer when parking.

I fought it for 2 years before I purchased a used FEM and had Ford program it to my 2003. They said it would not work but after the used FEM was installed and reprogrammed everything was finally fixed!
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JustALs

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I cleaned the maf with crc maf cleaner , changed the plugs with autolite copper because cheap. not until now I just noticed that forscan tells me my fuel pressure drops to 0 at WOT, and about 60kpa at half thottle and 275kpa at cruise
the injectors / fuel filter are clean. does this tell me its 100% the fuel pump?
 

joegr

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How about it 100% could be your fuel pump.. Which one, the primary is more likely than the jet pump, but... Of course, what if it is the pressure sensor instead? What if something is failing in the driver circuit in the REM?

In short, it's too complicated to know for certain without doing some tests. Since most don't have the tools needs for those tests, usually they throw parts at it, from the most likely to the least likely. (I'm not saying that this is invalid, there does come a point when it starts to be the most reasonable approach...)
 

JustALs

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thanks for the info joe, I think I will throw a pump at it since it been doing this loud growling/grinding noise too, will a delphi FE0420 pump fit the primary pump assembly?
 

JustALs

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would unplugging the fuel rail pressure sensor default to max rail pressure or whatever the pump can do?
 

JustALs

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Got a new pump coming my way and , and i hear a spark knock
 
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JustALs

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new pump in runs perfect thx the pressure actuallly rises on WOT ..
just need to find a coil apring for my rear shock it broke and cant source any from carparts they wont respond and no local junkyard has ls not sure what to do maybe going to have to do the bilstein conv
anyways
big thanks to everyone here been great info for a youngin with few kids and saved a shit ton of money and this inflation crazy lol pce out guy
 

JustALs

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saved the old pump for a spare but this is what the strainer looked like , probably gave the pump a hard time
was the original pump and let go at 300000km

Screenshot_20220816-000230~2.png
 

04_Sport_LS

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Most springs have paint color codes on them... and a plastic tag on them (if you are lucky) with a part # on the tag.

Might take some leg work to find a used spring, but the right one is out there somewhere.

I wouldn't do just the rear springs and shocks (Bilstein conversion). That will change the handling in a bad way.

It will make the LS "nose heavy". The back end will want to "come around" on you in turns.
 

clubairth

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That pump has earned it's keep! Throw it away and don't look back.
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