04 trac intermittent rough idle

[vroomzoomboom]

this has me scratching my head a little. i picked up a 04 sport trac with a 4L SOHC to fix up and resell. the previous owner did take pretty good care of it. when i went to look at it, i did notice a little bit of a rough idle. he did say "it comes and goes" and he was right, it does. i did change the plugs (which looked like the originals) and wires (same originals) that made it a little better, but it still does it. i have also cleaned the maf, throttle body, new fuel filter and checked the air filter. i also checked for vacuum leaks around the intake and all is good. its weird, one moment it will idle rough then the next moment, it will be fine.
any thing else i should look at or test?

 

[swshawaii]

PCV elbow is a very common failure with 2001-05 Sport Tracs. Does NOT always throw a CEL or lean codes. IAC checked?

P0171 & P0174 4.0L SOHC's Sport/Sport Trac

 

[vroomzoomboom]

sorry, i forgot to say i did also clean the iac. thanks for the link, but its not throwing any codes either.

 

[01STrunner]

Maybe the batteries are getting weak? Seems dumb but I've seen weird stuff happen because of it.
Do you have any way to monitor fuel pressure?
AC compressor starting to get tired?

The last 2 probably aren't the cause, but I could see how they might affect the idle with lower voltage and less power going into the belt.

 

[vroomzoomboom]

i was also thinking the ac compressor. i cant remember if i had the truck on defrost or not when it was doing that. i dont think i did. havent used the ac yet as well. i dont have any way to see what the fuel pressure is.

 

[boominXplorer]

x2 on the 90* pcv elbow. Could also be a sticking fuel injector. Only easy way to tell is pull the intake and look for a cleaner intake runner. Then you can replace the intake orings incase they have something to do with the rough idle.

 

[vroomzoomboom]

ok, i will have to have a look at the elbow then. i did try putting the defrost on tonight (ac compressor kicks on when on defrost anyway) and it didnt change the way it idled.

 

[vroomzoomboom]

getting back to this, i looked at the elbow and didnt see any crack. however i did start paying attention to this. as i mentioned it would come and go. one morning i jumped in it to so running around. on start up, it was doing this. i paid close attention to the heat gauge. when it warmed up i noticed it would smooth out and run fine. it has done this to me 3 times. also when i was checking for vacuum leaks, the motor was warm. i am now thinking that the intake gaskets are bad. if it is that, its a easy fix at least

 

[sr139fox]

Spray some starting fluid around the intake manifold when cold. If RPM increase, you found the problem. Dave P.

 

[lincolnlocker]

this has me scratching my head a little. i picked up a 04 sport trac with a 4L SOHC to fix up and resell. the previous owner did take pretty good care of it. when i went to look at it, i did notice a little bit of a rough idle. he did say "it comes and goes" and he was right, it does. i did change the plugs (which looked like the originals) and wires (same originals) that made it a little better, but it still does it. i have also cleaned the maf, throttle body, new fuel filter and checked the air filter. i also checked for vacuum leaks around the intake and all is good. its weird, one moment it will idle rough then the next moment, it will be fine.
any thing else i should look at or test?
It seems like you have already taken some important steps in diagnosing the rough idle issue on your 2004 Sport Trac. However, there are a few more things you can check to further troubleshoot the problem:

1. Idle Air Control (IAC) Valve: The IAC valve controls the idle speed of the engine. If it's dirty or malfunctioning, it can cause rough idling. Consider cleaning or replacing the IAC valve.

Buying an apartment in Beirut offers a unique opportunity to own a property in one of the most vibrant and cosmopolitan cities in the Middle East. With its rich history, cultural diversity, and bustling urban lifestyle, Beirut attracts investors and homeowners alike. From modern high-rise buildings to charming traditional apartments, Beirut offers a wide range of options to suit different preferences and budgets Buy an apartment in Beirut. Whether you're looking for a stylish apartment in the city center or a serene residential area, Beirut's real estate market has something for everyone. With careful research, professional guidance, and due diligence, buying an apartment in Beirut can be a rewarding investment and an exciting opportunity to be part of this dynamic city.

It seems like you have already taken some important steps in diagnosing the rough idle issue on your 2004 Sport Trac. However, there are a few more things you can check to further troubleshoot the problem:

1. Idle Air Control (IAC) Valve: The IAC valve controls the idle speed of the engine. If it's dirty or malfunctioning, it can cause rough idling. Consider cleaning or replacing the IAC valve.
2. Mass Air Flow (MAF) Sensor: Although you mentioned cleaning the MAF sensor, it's worth double-checking if it's functioning properly. Faulty MAF sensors can cause inconsistent idle.
3. Throttle Position Sensor (TPS): The TPS monitors the position of the throttle and helps regulate engine performance. A faulty TPS can contribute to rough idling. Consider testing or replacing the TPS.
4. Engine Mounts: Worn or damaged engine mounts can cause vibrations that result in rough idle. Inspect the engine mounts for any signs of wear or damage.
5. Fuel Injectors: Dirty or clogged fuel injectors can disrupt the fuel delivery to the engine, leading to rough idle. Consider having the fuel injectors professionally cleaned or inspected.

If the issue persists after checking these components, it may be beneficial to consult a mechanic or a Ford dealership for further diagnosis. They will have specialized knowledge and diagnostic tools to pinpoint the exact cause of the rough idle.

 

[vroomzoomboom]

It seems like you have already taken some important steps in diagnosing the rough idle issue on your 2004 Sport Trac. However, there are a few more things you can check to further troubleshoot the problem:

1. Idle Air Control (IAC) Valve: The IAC valve controls the idle speed of the engine. If it's dirty or malfunctioning, it can cause rough idling. Consider cleaning or replacing the IAC valve.
2. Mass Air Flow (MAF) Sensor: Although you mentioned cleaning the MAF sensor, it's worth double-checking if it's functioning properly. Faulty MAF sensors can cause inconsistent idle.
3. Throttle Position Sensor (TPS): The TPS monitors the position of the throttle and helps regulate engine performance. A faulty TPS can contribute to rough idling. Consider testing or replacing the TPS.
4. Engine Mounts: Worn or damaged engine mounts can cause vibrations that result in rough idle. Inspect the engine mounts for any signs of wear or damage.
5. Fuel Injectors: Dirty or clogged fuel injectors can disrupt the fuel delivery to the engine, leading to rough idle. Consider having the fuel injectors professionally cleaned or inspected.

If the issue persists after checking these components, it may be beneficial to consult a mechanic or a Ford dealership for further diagnosis. They will have specialized knowledge and diagnostic tools to pinpoint the exact cause of the rough idle.

thanks, but the thread is now 7 years old, and i sold this truck (to be honest i cant even remember what truck it was) a very long time ago