Here is my problem: My 2001 Screw 5.4 (95K miles) has no low end power. This has been going on for about 2 months. From idle to about 2200 rpm it just bogs and feels like it might have a slight misfire. Once it gets to 2200 RPM it runs perfect. It is barely noticeable, if at all with the A/C off, but if the A/C is cranked on high or I am towing it makes me cautious pulling out into traffic. I have an EDGE tuner, so I tried pulling any diagnostic codes, but I have no CEL, so no codes to pull.

What I have done is: change the transmission fluid, and fuel filter (this afternoon), clean the air filter, changed spark plugs 15K miles ago, and returned the tune to stock. None of this helped, but needed to be done regardless.

What I am going to do is: Change the COPS again (did the ebay ones 35K miles ago).

My question is, what else, if anything should I do? And if it is the COPS or one of them going bad, why won't it throw a CEL. Is there a way to force a CEL. I hate changing the COPS at the back of the motor.

 

when is the last time you changed the plugs? cleaned the iac? cleaned the air filter? cleaned the MAF?

 

Plugs: 15K miles ago
IAC: not sure what that is, so I am going to say never cleaned
MAF: 30K miles ago
Air Filter: 3 hours, 8 miles ago

 

^ Idle Air Control motor. I would clean the MAF again too.

 

Thanks for the input. I'll clean the MAF and IAC tomorrow.
According to some other threads the IAC is a silver canister somewhere around the throttle body. Is this correct? Also, the other thread said to just clean it with WD-40. Just spray it in and let it dry, right?

 

yup, let it dry good

 

Does the 5.4 2v have a IMRC? If it does, that sounds like a possible symptom, it's stuck.

 

I don't know if the 5.4 2V has IMRC (intake manifold runner control). This is the 1st time I am hearing about it. I have heard of the 3V engines having CMCV (charge motion control valve) which I guess is similar. What is it, and where is it?

However, I cleaned my MAF and IAC this morning, and my truck is running like new again. The MAF looked spotless, but cleaned it anyways since I had it out. The IAC definitely looked like I have never cleaned it, since I haven't. I filled it with WD-40, and black sludge came out of it. Swabbed it clean with a couple of Q-tips, sprayed it again and let it dry. Put it all back together and truck runs great again.

The idle is noticeably smoother now, and I hadn't realized that the idle was rough at all until doing this. The real test is going to be pulling my boat next weekend, since this weekend is just about shot.

Thank you all who helped me with this problem. My next step would have been new COPS and pulling injectors. So, you saved me a ton of money and unnecessary work.

 

I JUST GOT A 2001 4X4 EXPD WITH A 4.6 AND WITH 141K ON IT, I NOTICED THAT THE RPMS JUMP FROM 500 TO 750 NO CEL IS ON, I LOOKED UNDER THE TRUCK AND NOTICED TAT THE TRUCK FUEL FLITER IS RUSTED AS IF IT WAS NEVER CHANGED, IM GOING TO CHECK THE IAC TO SEE IF ITS DIRTY, ANY OTHER ITEMS I SHOULD CHECK

 

^ Need to check your caps lock first...

 

I DONT FEEL CAPS IS A BIG DEAL, WHEN WE ARE TRYING TO HELP EACH OTHER OUT, I ALWAYS USE CAPS THATS HOW I HAVE ALWAYS TYPED.
BUT THANKS FOR THE NON RELATED REPLY

HAPPY MOTHERS DAYS

 

Its improper to type with all caps. It really is.

Obviously change the fuel filter. Sounds like if the prev owner couldnt do something as simple as change a fuel filter in the last 5 years for $10 there might be some other negligent issues. If you just bought it, check and make sure your oil filter is a good brand, preferably motorcraft, not fram. Spend a day and go through the motor, clean the throttle body, IAC and MAF. Check your pcv valve and make sure its operating correctly and is a motorcraft part. Check the pcv hose from the valve all the way around to the back of the throttle body, easiest is when you have the throttle body removed. They are known for cracking and can cause idle and running issues. If you ever get time to battle checking the plugs, that would be a good idea also. Check your coolant for color, check all your fluids including power steering, tranny, brake and oil for dark colors or burnt smells. Other than that, keep good 5/20 oil in it with a motorcraft filter and it will treat you good.

GOOOD LUUUCKKK AND HAPPY MOTHERSDAY TO YOU TOO BUDDY>.. see its not that cool eh

 

thanks for the update will take a look at items mentioned,
didnt know everyone was sensitive about the caps will keep it mind
Tnxz
Dayalalito01

 

Thanks for responding positivly. All caps in a post indicates yelling, or anger, but makes it difficult to read for most of us.

 

Can someone point me towards a detailed step-by-step of how to clean the IAC (and locate it)? I've got the same problem the OP had - no low end power. When pulling my trailers or starting from a dead stop it's extremely noticeable.