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99 crown vic hesitation help!!
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Xxvicman
Novice
Jun 25, 2010, 10:51 PM
Post #1 of 8
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99 crown vic hesitation help!!
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hi, im experiencing hesitation at light throttle between 50-55mph and sometimes at 45 and ive done the following:
replaced spark plugs and coils with motorcraft
replaced fuel filter
cleaned MAF sensor
took it to a trans expert and he said its not the transmission also got a trans filter and fluid replacement
got a catalytic converter restriction test and it was good
i have a P0420 catalytic efficiency code below threshold bank 2 but its been there way before i started having this problem
any advise? thx in advanced!.
btw its a 1999 crown victoria police interceptor with 135,xxx miles
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Sidom
Veteran
/ Moderator
Jun 26, 2010, 6:55 PM
Post #2 of 8
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Re: 99 crown vic hesitation help!!
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Some of these can be tough to diag...
Sounds like you've already done some good maintenance things & using good parts, so for the time being that area can be put on the back burner.... What did you clean the MAF sensor with?
Was the P0420 the only code it has? Was the KOEO & KOER tests also run?
A couple of quick things you could try would be to take it out of O/D and see if it makes a difference on the miss, also try disconnecting the EGR valve & take it for a spin....
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Xxvicman
Novice
Jun 26, 2010, 7:12 PM
Post #3 of 8
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Re: 99 crown vic hesitation help!!
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thx for replying.
i cleaned the MAF with a can of MAF cleaner from autozone.
and yea P0420 is the only code it has and as far as the KOEO and KOER im not sure about that
and ive tried with OD off and no changes its still the same and ive tried taking the hose off the EGR still the same
the hesitation feels more like a misfire but it feels like its coming from underneath the car im gonna get a compression tester and check the cylinders monday
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Sidom
Veteran
/ Moderator
Jun 26, 2010, 7:42 PM
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Re: 99 crown vic hesitation help!!
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That would be good.....
Normally if you are getting a miss like that, it will set a code to help narrow the search....
THE THING with those older Fords.. Depending on when the codes were cleared... In order for it to set a misfire code, the crank profile has to be relearned and that can take some time. It could have a miss so bad the engine is jumping out of the compartment & it won't code. Even worse on the PID list under misfire moniter it will say YES!!!! even when the crank profile hasn't been learned.
I don't know if your scanner has Mode $06 capabilities but there is a test (TID 53) that will show misfires even when the profile isn't relearned. It's not live but way better than nothing..
I would have to look up the procedure for the relearn to be sure but its something like you have to accelerate from 40mph to 60mph and then coast for 10 seconds, you can't touch the brk, turn the wheel, nothing (basically a 0 ms injector pulse width), as soon as you do, it stops the relearn. AND you have to do this 3 times for the profile to be relearned.......
(This post was edited by Sidom on Jun 26, 2010, 7:43 PM)
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Xxvicman
Novice
Jun 26, 2010, 7:57 PM
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Re: 99 crown vic hesitation help!!
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good info... i actually go to autozone and get the codes read cuz i dont have the money to buy a scanner my self yet
also i heard that the relearn process is crazy and takes a long time
(This post was edited by Xxvicman on Jun 26, 2010, 10:59 PM)
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Xxvicman
Novice
Jun 29, 2010, 10:44 AM
Post #6 of 8
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Re: 99 crown vic hesitation help!!
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well i checked the compression of each cylinder and they all read 110
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 29, 2010, 11:13 AM
Post #7 of 8
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Re: 99 crown vic hesitation help!!
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Xxviceman: Sidom is on this and can handle this. I just question the uniformity so exactly of that compression test. Just how did you do that and did you also do a "wet" test? To me that's uniformly too low and unrealistically to even. May be how test was done, the gauge off or something doesn't jive with the results - IMO. Can't think of one single issue that would cause that so easily on this engine. Sidom can expound from those results as he may know this engine better than I do,
T
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Xxvicman
Novice
Jun 29, 2010, 9:01 PM
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Re: 99 crown vic hesitation help!!
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well i used a cheap gauge from autozone and i got around 115 and 120 for all cylinders, also i couldnt tighten the gauge all the way down in the spark plug well so some air leaked, so i think it wouldve been higher
(This post was edited by Xxvicman on Jun 30, 2010, 1:31 AM)
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