99 F250 SD hesitation

1fomocofan · 10-29-2009, 03:38 PM

Need some ideas. 5.4L Auto started hesitating after sitting for three weeks. So far have ohmed all the plug coils and the injectors they were all fine. Changed the fuel filter today and checked fuel pressure (which is at 30 psi). Also at the same time this started, the fuel guage started going random, sometimes it reads correctly and other times it doesnt. Any ideas would be greatly appreciated.

mudseeker · 10-29-2009, 03:43 PM

fuel pressure seems low...........

mrjohnwayne · 10-29-2009, 04:49 PM

ditto, seems like weak fuel pressure to me.

eponator · 10-29-2009, 05:21 PM

I would have to agree and I've got a 350 with a 5.4 if that helps. How many miles are on the truck and how often do you change your fuel filter?

Crmzendrgone · 10-29-2009, 05:26 PM

Agreed pressure seems low. Does ford have a one way flow fuel filter, if so could it be in backwards?

1fomocofan · 10-29-2009, 05:51 PM

1. The truck has 153,000, have owned it for the last 20k, and changed the fuel filter today for the first time since I owned it.
2. Yes it has a one way filter on it, no it is not on backwards. Had the problem before I changed the filter.
3. I might add that when turning the key to "on" I have 42 psi, and when it starts it goes down to 30. The manual I have says 30-45psi, but that seems like a large range to me, and I am on the bottom of it. Where should the pressure be at in your opinion, and can I increase it?

Case 7230 · 10-30-2009, 01:22 PM

I would have thought you should have about 35lbs at idle and around 42lbs at WOT.
With engine running pull the vacuum line off the fuel pressure regulator and see if the fuel pressure goes up to the 42lbs.

1fomocofan · 10-30-2009, 06:22 PM

Case,I did that today, and yes it goes up to 42. After talking to the Ford garage I replaced all 8 plugs and boots today and seems to be smoother, however can still feel hesitation a little bit but not nearly what it was. Put pressure gauge on and ran it through the back of the hood so I could see it while driving. At WOT I have about 42psi, however did notice that at about 1500rpms the needle on the pressure gauge was not holding steady (32-36psi), does that seem normal? Also I have no codes.

Case 7230 · 10-31-2009, 03:02 AM

From what you have said I would think the fuel pump is OK. Might be worth tossing a can of a good fuel injector cleaner into the fuel tank and running that through.

1fomocofan · 10-31-2009, 06:11 AM

Have ran a bottle in the last two tanks, not sure if it was in my mind or not but I swear after the first tankful it seemed to run better. Wondering about EGR valve, any ideas? Problem does seem to increase with engine warm up. I appreciate all of the responses.

10-29-2009, 03:38 PM	#1
1fomocofan Junior Member Join Date: Oct 2009 Location: Iowa Posts: 6	99 F250 SD hesitation Need some ideas. 5.4L Auto started hesitating after sitting for three weeks. So far have ohmed all the plug coils and the injectors they were all fine. Changed the fuel filter today and checked fuel pressure (which is at 30 psi). Also at the same time this started, the fuel guage started going random, sometimes it reads correctly and other times it doesnt. Any ideas would be greatly appreciated.

10-29-2009, 04:49 PM	#3
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,789	ditto, seems like weak fuel pressure to me. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

10-29-2009, 05:21 PM	#4
eponator Senior Member Join Date: Nov 2008 Location: SO Cal Posts: 772	I would have to agree and I've got a 350 with a 5.4 if that helps. How many miles are on the truck and how often do you change your fuel filter? __________________ '99 F350 5.4L crewcab Longbed

10-29-2009, 05:26 PM	#5
Crmzendrgone Senior Member Join Date: Apr 2009 Location: Arizona Posts: 3,167	Agreed pressure seems low. Does ford have a one way flow fuel filter, if so could it be in backwards? __________________

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10-29-2009, 03:43 PM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,155	fuel pressure seems low...........

10-29-2009, 05:51 PM	#6
1fomocofan Junior Member Join Date: Oct 2009 Location: Iowa Posts: 6	1. The truck has 153,000, have owned it for the last 20k, and changed the fuel filter today for the first time since I owned it. 2. Yes it has a one way filter on it, no it is not on backwards. Had the problem before I changed the filter. 3. I might add that when turning the key to "on" I have 42 psi, and when it starts it goes down to 30. The manual I have says 30-45psi, but that seems like a large range to me, and I am on the bottom of it. Where should the pressure be at in your opinion, and can I increase it?

10-30-2009, 01:22 PM	#7
Case 7230 Senior Member Join Date: Dec 2007 Posts: 665	I would have thought you should have about 35lbs at idle and around 42lbs at WOT. With engine running pull the vacuum line off the fuel pressure regulator and see if the fuel pressure goes up to the 42lbs.

10-30-2009, 06:22 PM	#8
1fomocofan Junior Member Join Date: Oct 2009 Location: Iowa Posts: 6	Case,I did that today, and yes it goes up to 42. After talking to the Ford garage I replaced all 8 plugs and boots today and seems to be smoother, however can still feel hesitation a little bit but not nearly what it was. Put pressure gauge on and ran it through the back of the hood so I could see it while driving. At WOT I have about 42psi, however did notice that at about 1500rpms the needle on the pressure gauge was not holding steady (32-36psi), does that seem normal? Also I have no codes.

10-31-2009, 03:02 AM	#9
Case 7230 Senior Member Join Date: Dec 2007 Posts: 665	From what you have said I would think the fuel pump is OK. Might be worth tossing a can of a good fuel injector cleaner into the fuel tank and running that through.

10-31-2009, 06:11 AM	#10
1fomocofan Junior Member Join Date: Oct 2009 Location: Iowa Posts: 6	Have ran a bottle in the last two tanks, not sure if it was in my mind or not but I swear after the first tankful it seemed to run better. Wondering about EGR valve, any ideas? Problem does seem to increase with engine warm up. I appreciate all of the responses.

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