Rough Idle on 2003 F-150 5.4L
fatboy-74

AOL

#21 Nov 19, 2006
Tom Ferrari wrote:
I have flushed the fuel injectors and no codes show up on the computor.At 40mph and above skip goes away,at idle, rough.
change your plugs wires and boots this should correct the problem
Jeff Wallace

Jacksonville, FL

#22 Nov 23, 2006
I have a 2000 Expedition 5.4 with 93000 mi. Engine began missing at 1200-1500 rpm. Replaced coil packs engine ran fine for about 2 weeks. Started missing again. My local mechanic pulled #8 plug and found coolant in the plug hole. I then took it to the local Ford dealer for them to diagnose. They informed me that I had a cracked block. I Find this hard to believe. I bought this vehicle with apprx.20000 mi. on it and have had it regularly maintained and it has NEVER run hot. Any suggestions? Thanks
Sheba

United States

#23 Nov 29, 2006
I have just bought an old F150 XL and want to gewt it looked over by an experienced mechanic, with a view to doing some modifications too it. Any suggestions of 4x4 specialists? Close as possible to West Hollywood, LA. I tried calling Ford and they won't work on trucks older than 10 years. Thanks.
jim blount

Odessa, TX

#24 Dec 2, 2006
MARK wrote:
I have just punchiest a 2003 f-150 4x4 5.4L, the engine compartment was extremely dirty, so I pressure washed the compartment. Since the truck has a rough idle most of time. Any suggestions please
replace front plug on passenger side
jim blount

Odessa, TX

#25 Dec 2, 2006
replace front plug on passanger side
Joshua

Fpo, AP

#26 Dec 7, 2006
I have a 2001 F150 with the 4.6L in it. It has 89,000 mi and it is just now starting to run a little rough. I am pretty sure it is the Coil on Plugs wearing out. I have gone to every online part store I could imagine to order them, but every resource tells me that the 2001 with the 4.6 is supposed to use spark plugs and only the 5.4 uses the coil on plugs. Well my truck most definately has coil on plugs and is not a 5.4. I cant order them with out guessing which part number to order. Do you have any guidance on this?
Frank

AOL

#27 Dec 8, 2006
Frank

AOL

#28 Dec 8, 2006
Another tactic is to hold the gas pedal to the floor with the engine running.... That should clear things out!
Roger

Palo Alto, CA

#29 Dec 11, 2006
I have a f-150 4.2 liter truck 6 cylinder. I am getting a 171 and 174 code. I have changed the spark plugs and wires, fuel filter, cleaned the egr valve, cleaned the maf sensor, changed one O2 sensor. I have getting a slight hesitation when driving and bad gas mileage. Can anyone advise as to how to correct this?

Thank you.
Ron28

Baton Rouge, LA

#30 Dec 11, 2006
Roger wrote:
I have a f-150 4.2 liter truck 6 cylinder. I am getting a 171 and 174 code. I have changed the spark plugs and wires, fuel filter, cleaned the egr valve, cleaned the maf sensor, changed one O2 sensor. I have getting a slight hesitation when driving and bad gas mileage. Can anyone advise as to how to correct this?
Thank you.
Did you change your air filter? Both of those codes indicate a lean fuel mixture. OBD code 171 System to lean (Bank 1) and OBD code 174 System to lean (Bank 2. Check to see if your air filter is dirty, that would also explain the hesitation.
tomkat

Foxboro, MA

#31 Dec 11, 2006
04 f150 5.4l 34000 after letting truck sit for 2 days on start up truck blows white smoke smells like carbon.also burning oil every 3000
Frank

AOL

#32 Dec 11, 2006
Do all of you guys race these trucks? remove the battery cables and trun on the lights for 30 mins to kill the codes. Double check everything and start. Let idle for about 20 mins and then drive normally.... Other than that refer to my Dec. 8, posting maybe that will help?
Ron28

Baton Rouge, LA

#33 Dec 12, 2006
Ron28 wrote:
<quoted text>
Did you change your air filter? Both of those codes indicate a lean fuel mixture. OBD code 171 System to lean (Bank 1) and OBD code 174 System to lean (Bank 2. Check to see if your air filter is dirty, that would also explain the hesitation.
I made a mistake and gave you the wrong advice. Codes 171 and 174 would not indicate a dirty air filter it would probably indicate a clog fuel filter or a vacuum leak somewhere in your engine. Because you are getting to much air. Also remember when you think you have corrected the problem you have to erase the codes because they want reset automatically.
gman4reel

Nassau, Bahamas

#34 Dec 12, 2006
I am experiencing the same problem with my 2002 4.2 XL. I replace air,fuel filter,MAF sensor, front,back ,02 sensors,I erase the codes and still P0171,and P0174 returns after about 150 miles . Can anyone help with that?
Ron28 wrote:
<quoted text>
Did you change your air filter? Both of those codes indicate a lean fuel mixture. OBD code 171 System to lean (Bank 1) and OBD code 174 System to lean (Bank 2. Check to see if your air filter is dirty, that would also explain the hesitation.
Roger

Palo Alto, CA

#35 Dec 13, 2006
Ron 28

I am currently using a performance "Air raid" air intake system. However, I am cleaning it with a K&N cleaning kit. Do you think this may be the problem? Also, I noticed that my filter itself is missing two out of the 4 screws to fasten it. Huh. Where else would I be getting excess air. Do you think it would make a difference if I change the other O2 sensor.

DickHead

AOL

#36 Dec 13, 2006
Read Franks Post above to fix!
Roger

Palo Alto, CA

#37 Dec 13, 2006
How about the pcv valve. Could this be the problem. I have been meaning to change this out however I have not been able to. I can not locate it. Can this be the problem if so where is it located.
Ron28

Baton Rouge, LA

#38 Dec 13, 2006
gman4reel wrote:
I am experiencing the same problem with my 2002 4.2 XL. I replace air,fuel filter,MAF sensor, front,back ,02 sensors,I erase the codes and still P0171,and P0174 returns after about 150 miles . Can anyone help with that?
<quoted text>
If you changed all that stuff and you are still getting those codes. It seems like it's a good chance you have a vacuum leak. My advice would be open the hood an inspect every thing connected to a vacuum line and listen for a leak, you might have to rev the engine a little. Here is the logic of what could be going on, air is being sucked into the engine somewhere it shouldn't, as a result your engine is getting to much air causing the fuel mixture to be too lean, therefore setting code 171 and 174. It might be a gasket, hose or cracked plastic, but it has to be something that affects both sides of the engine. Probably something connected to the throttle body. For instance a bad O2 sensor would not set both banks 1 ond 2 it would set a code for the bank that's faulty.(Bank 1 means the side of the engine with the number 1 cylinder and bank 2 means the other side). Four cylinder engines only have 1 bank

This seems to a code that a lot of people seem to having trouble with. Sometimes it's simple as a dirty fuel filter. But vacuum leaks can be a little more tricky to catch . Does anyone else have advice?
gman4reel

Nassau, Bahamas

#39 Dec 14, 2006
hey guys problem found,vacuum leak I sealed off the air intake the applied air pressure to the plenum from my air compressor and discovered air leaking from the plenum gasket.
thanks guys for the advice , wish I had done that sooner it would have saved me some funds. Well I guess you live and learn.
Ron28 wrote:
<quoted text>

If you changed all that stuff and you are still getting those codes. It seems like it's a good chance you have a vacuum leak. My advice would be open the hood an inspect every thing connected to a vacuum line and listen for a leak, you might have to rev the engine a little. Here is the logic of what could be going on, air is being sucked into the engine somewhere it shouldn't, as a result your engine is getting to much air causing the fuel mixture to be too lean, therefore setting code 171 and 174. It might be a gasket, hose or cracked plastic, but it has to be something that affects both sides of the engine. Probably something connected to the throttle body. For instance a bad O2 sensor would not set both banks 1 ond 2 it would set a code for the bank that's faulty.(Bank 1 means the side of the engine with the number 1 cylinder and bank 2 means the other side). Four cylinder engines only have 1 bank
This seems to a code that a lot of people seem to having trouble with. Sometimes it's simple as a dirty fuel filter. But vacuum leaks can be a little more tricky to catch . Does anyone else have advice?
gman4reel

Nassau, Bahamas

#40 Dec 14, 2006
I learned this the hard way. Before you buy any parts pressure test your system first some leaks you may not HEAR or see with the engine running. I seal ed off my air intake with a piece of inner tube and hose clamp then I unhooked the hose from my brake booster and applied air from my air compressor and discovered air escaping from the plenum gasket. Yours might be there or somewhere else. That is how mine was detected. A very inexpensive way.
Roger wrote:
How about the pcv valve. Could this be the problem. I have been meaning to change this out however I have not been able to. I can not locate it. Can this be the problem if so where is it located.

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