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#2686204 - 03/24/13 09:17 AM hello guys my first time posting!
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
Well i have a 99 p71

She started to "misfire" so i replaced plugs and coils.
The problem started with a constant pulsing at cruising speeds wether is had been 30 or 70.
Once ive done this the issue has gotten much worse.
Replaced tc, no change. Tested fuel jnjectors all good. Coils all good.
Catalysts werr getting hot, had them removed no change.

It does this stumble constantly now, getting progressovely worse. MUCH WORSE GOING UP.HILL

Does anyone else agree fuel pump?

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#2686210 - 03/24/13 09:23 AM Re: hello guys my first time posting! [Re: zfxp99]
GrandMarq9807 Offline
Over the Hill

Registered: 05/10/10
Posts: 4420
Loc: Virginia
Only way to know is test fuel pressure, otherwise you're just throwing parts at it... Have you read the codes???

Any drivabilaity problem should start with cleaning the MAF, simple, cheap and fixes probably 40-50% of the issues that are reported...
_________________________
1998 Grand Marquis LS. 96K mi. .. Stock
2007 Grand Marquis GS. 90K mi. .. Stock
1996 F-150 XLT 196K mi Beater, Stock

----------My Toys---------(links are up)
1969 Fairlane Cobra 428CJ 4-Speed
1972 Comet GT Restomod 306, C4
1988 Turbo Coupe 331 AOD & 3.73 .. Pressurized ½ Motor is History

*****************NEW TOY!!!*********************
1969 Base Fairlane 302, C4, 45K mi(really!)

Now with P/S & PDB
Gonna wake it up with a Blue Print headed 347




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#2686217 - 03/24/13 09:31 AM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
Is there a guide showing how to do this?

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#2686225 - 03/24/13 09:36 AM Re: hello guys my first time posting! [Re: zfxp99]
cragantler1 Offline
Over the Hill

Registered: 11/19/07
Posts: 1800
Loc: Fla. Cracker in South Conway
Search is your friend
https://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=1153795#Post1153795
BOK has a ton of tips for you.
Welcome from a Floridian in Maine
_________________________
2004 Arizona Beige P-73, gone but never forgotten


Click to reveal...
2004 P-73,113k+
Performance & Handling:
P-71 H-pipe with Flowmaster 50s/Rear Meow delete/ADTR P&P plenum/70mm TB/Marauder swaybars/MZT/BOC tune/J-Mod/ 2006 P-71 rear coils/Gatorback belt/2005 17" Mustang GT Premium rims with Pirellis/ FRPP 3.55's / FRPP Trak-Lok
best time, pre-gear change: 15.4 @ 91.6mph

Appearance:
Honeycomb color matched grille/lower grille mesh mod/S-55 tail/reverse lights mod/bumper tuck/window chrome and wood dash delete/black reflective rear fascia/side marker mod/15% rear, 35% front tint/Marauder gauge cluster/1999 Lincoln Continental console and floor shift/Marauder gauge pod with "real" Autometer gauges/ Ford Focus driving lights with 5000K HID's wired to Marauder light switch for factory operation/repaired LCM/Marauder corner lights


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#2686253 - 03/24/13 10:21 AM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
I found this EXACT guide after i searched lol. ive done this already. Still stumbling n bumbling

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#2686261 - 03/24/13 10:33 AM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
If you disconnect your egr valve and no change in idle, thats a problem correct?

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#2686262 - 03/24/13 10:35 AM Re: hello guys my first time posting! [Re: zfxp99]
BigMerc96 Offline

I know nothing
Posting Addict

Registered: 06/05/10
Posts: 19868
Loc: I can see Detroit from here!
I'd do a compression test on it to rule out a mechanical issue in the engine.
_________________________
-Steve

2006 Audi A6 ~132k miles, stock.
1998 Mercury Grand Marquis LS HPP ~100k miles, slowly acquiring modifications.
1997 Town Car Cartier ~145k miles, Ported Plenum, Gutted Airbox, Contour E-fan Retrofit, Dual exhaust with Magnaflows, cats deleted, MSD Ignition, KYB Gas-A-Justs, P71 front bar, air ride reinstated, Projector retrofit, Caddy 4-note horn retrofit, Wood rim steering wheel retrofit, holistic weight reduction as the parts fall off..
1996 Mercury Grand Marquis GS 117,485mi. R.I.P. 7/14/12 frown

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#2686269 - 03/24/13 10:45 AM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
Ive done that already. I cleared.
Also im not throwing any misfire codes at all.
Im thinking i have a vacuum leak. But i always thought they only reared their ugly little hrwds up at idle...


Edited by zfxp99 (03/24/13 10:48 AM)

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#2686276 - 03/24/13 10:52 AM Re: hello guys my first time posting! [Re: zfxp99]
Rolling-Thunder Offline
Member

Registered: 04/25/02
Posts: 498
Loc: Albany, NY
Have you tried driving the car with the MAF sensor unplugged?

Just because it is clean, doesn't mean it isn't going bad.

I would do that before trying anything else.
_________________________
2014 Escape, model S - white
2003 Crown Vic Sport - spruce green
MZT mod, 180 T-stat, NGK 4177 plugs, 21mm sway bar, fuel tank shield kit, Sil-blade low profile wipers


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#2686277 - 03/24/13 10:54 AM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
When its unplugged idle evens out, but when i give it a little gas, it stutters, is that supposed to happen? Lol

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#2686299 - 03/24/13 11:59 AM Re: hello guys my first time posting! [Re: zfxp99]
stalag Offline
Over the Hill

Registered: 03/29/09
Posts: 3978
Loc: Columbus, OH
Originally Posted By: zfxp99
When its unplugged idle evens out, but when i give it a little gas, it stutters, is that supposed to happen? Lol


In short, yes. Unplugging the MAF turns off both the O2 sensors and the MAF sensor and sends the computer into a default limp mode. Chances are you either have either O2 sensors that need to be changed because they are "lazy" or a MAF sensor. O2 sensors need to be changed due to the fact they can become contaminated and the heat/cool cycles also have an impact on how they read. Replace the O2 sensors if you do not know how long they have been in place and in any case they should be replaced every 80K miles. Removal of catalytic convertors is not recommended as it is illegal. Clean the MAF sensor with MAF cleaner or electrical contact cleaner. Use of carburetor cleaner is not recommended because the solvent will cause other damage. If this does not improve the MAF sensor, replacement should be done. It is a definite misconception and belief around here that unplugging the MAF is diagnostic for a bad MAF. This is BS tech.

On a separate note put the information for your car in the signature so you don't have to retype it each time.
_________________________
Stalag;___________Just for Rizzo I am posting this in my sig. Coolants
2001 Lincoln Town Car Cartier L, 1997 Mercury Grand Marquis (extinct)
On my LTC the following mods/upgrades were added. Heinous motorsport control arms, Command Automotive SD-1 rotors (these rotors can no longer be obtained), Calipers by Goldlinebrakes.com in silver with Hawk HPS pads (now running Ford OEM), MSD COP's. MZT is also applied with programming from BOC. j-mod is now done. Final rebuild of transmission done by Gearstar.

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#2686304 - 03/24/13 12:11 PM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
an o2 sensor would cause rough idle, and stuttering?

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#2686326 - 03/24/13 12:33 PM Re: hello guys my first time posting! [Re: zfxp99]
stalag Offline
Over the Hill

Registered: 03/29/09
Posts: 3978
Loc: Columbus, OH
Yes it can! O2 sensors used to set fuel trims. Malfunctioning O2 sensors can also cause a catalytic convertor to run hot. You mentioned a hot catalytic convertor. That is diagnostic of a failing O2 sensor. Failing O2 sensors will cause the car to run rich and will dump fuel into the catalytic convertors causing them to overheat and fail.
_________________________
Stalag;___________Just for Rizzo I am posting this in my sig. Coolants
2001 Lincoln Town Car Cartier L, 1997 Mercury Grand Marquis (extinct)
On my LTC the following mods/upgrades were added. Heinous motorsport control arms, Command Automotive SD-1 rotors (these rotors can no longer be obtained), Calipers by Goldlinebrakes.com in silver with Hawk HPS pads (now running Ford OEM), MSD COP's. MZT is also applied with programming from BOC. j-mod is now done. Final rebuild of transmission done by Gearstar.

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#2686331 - 03/24/13 12:38 PM Re: hello guys my first time posting! [Re: stalag]
Rolling-Thunder Offline
Member

Registered: 04/25/02
Posts: 498
Loc: Albany, NY
Originally Posted By: stalag
It is a definite misconception and belief around here that unplugging the MAF is diagnostic for a bad MAF. This is BS tech.



Have to disagree with you there.

When the MAF sensor started going south on my T-Bird, I went to Autozone, purchased a new one, and installed it in the parking lot. The MAF sensor was defective, and the car died on the way home. I unplugged the MAF, and drove the rest of the way home just fine.

How is this not a diagnostic method for a bad MAF ?


One of the assumptions that can be made is that if the engine runs better with the MAF unplugged, in comparison to it plugged in, then the MAF sensor can be bad.


Edited by Rolling-Thunder (03/24/13 12:40 PM)
_________________________
2014 Escape, model S - white
2003 Crown Vic Sport - spruce green
MZT mod, 180 T-stat, NGK 4177 plugs, 21mm sway bar, fuel tank shield kit, Sil-blade low profile wipers


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#2686334 - 03/24/13 12:42 PM Re: hello guys my first time posting! [Re: Rolling-Thunder]
stalag Offline
Over the Hill

Registered: 03/29/09
Posts: 3978
Loc: Columbus, OH
Originally Posted By: Rolling-Thunder
Originally Posted By: stalag
It is a definite misconception and belief around here that unplugging the MAF is diagnostic for a bad MAF. This is BS tech.



Have to disagree with you there.

When the MAF sensor started going south on my T-Bird, I went to Autozone, purchased a new one, and installed it in the parking lot. The MAF sensor was defective, and the car died on the way home. I unplugged the MAF, and drove the rest of the way home just fine.

How is this not a diagnostic method for a bad MAF ?


One of the assumptions that can be made is that if the engine runs better with the MAF unplugged, in comparison to it plugged in, then the MAF sensor can be bad.


Because unplugging the MAF sensor turns off both the O2 sensors and the MAF sensor. It also changes the fuel tables to run rich. It backs off timing to be safer. These changes are not isolative for the MAF alone. Replacing a MAF that is bad is just happenstance. This info comes from discussions with both Lonnie at BOC and with Ford techs.
_________________________
Stalag;___________Just for Rizzo I am posting this in my sig. Coolants
2001 Lincoln Town Car Cartier L, 1997 Mercury Grand Marquis (extinct)
On my LTC the following mods/upgrades were added. Heinous motorsport control arms, Command Automotive SD-1 rotors (these rotors can no longer be obtained), Calipers by Goldlinebrakes.com in silver with Hawk HPS pads (now running Ford OEM), MSD COP's. MZT is also applied with programming from BOC. j-mod is now done. Final rebuild of transmission done by Gearstar.

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#2686341 - 03/24/13 12:54 PM Re: hello guys my first time posting! [Re: zfxp99]
Rolling-Thunder Offline
Member

Registered: 04/25/02
Posts: 498
Loc: Albany, NY
O2 sensors are usually fine for about 150,000 miles, at which point, they should be replaced, as I did with my CV Sport. If I was having these symptoms with my car, I would certainly think that the MAF sensor is more likely the culprit.

The original poster can also do some diagnostic tests of his own on the MAF sensor, providing he has a voltmeter.
_________________________
2014 Escape, model S - white
2003 Crown Vic Sport - spruce green
MZT mod, 180 T-stat, NGK 4177 plugs, 21mm sway bar, fuel tank shield kit, Sil-blade low profile wipers


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#2686354 - 03/24/13 01:14 PM Re: hello guys my first time posting! [Re: Rolling-Thunder]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
I do, in fact have one.
when I get off of work I will test it.

So the maf can cause stutter and other symptoms?

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#2686505 - 03/24/13 06:13 PM Re: hello guys my first time posting! [Re: zfxp99]
sm41 Offline
Over the Hill

Registered: 10/19/10
Posts: 4071
Loc: Wilmington, NC
Yes, it most definitely will.

Also, which cats were removed? If only the backs have been cut, no issues should arise. If you removed the front pair though, that will throw a CEL.


Edited by sm41 (03/24/13 06:14 PM)
_________________________

2001 Crown Vic, 125k miles. Intake, exhaust, tune, 3.73s. Mr. Viccles
'89 Mustang LX. 5.0, T5, GT40 build incoming. Marengo
'89 Jeep Cherokee. AX-15 5 speed swap, 3" lift, 30" mismatched tires. el Burro
'86 Mustang GT. Napoleon Blownapart. R.I.P. in pieces
-Steven
Originally Posted By: Moby_Vic
And I knew a boat wasn't a good idea for a standoff. I hope Wrinklypants realizes that now.

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#2688191 - 03/27/13 06:09 PM Re: hello guys my first time posting! [Re: zfxp99]
zfxp99 Offline
n00b

Registered: 03/05/13
Posts: 13
Loc: florida
Well cleaned and tested maf, it tested well.
I'm smelling major fuel being dumped, and it's heating up the cats, on both sides..

There's only a few things that can do this correct?

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