so I may just be imagining things, but I thought I'd pass it by all you guys before I get too worried... so within the last 500-1000 miles, when im at a red light, or idling, my truck will just be sitting there (obviously) foot on the brake, and it will be really really smooth, and on about 15 sec. intervals it will have about 3-4 seconds of churning...you can feel it through the brake pedal- ---------^^^^^^---------------------^^^^^-------------
(diagram of what its like- yea its a bit literal but hey.) is this normal, or should I be aware of something bigger- if so, can you lead me to reference any TSB's, or other methods?

thanks guys-
running a 2005 FX4 SC. 3.73LS build date mid april, 2005. Dearborne.

gas wise, running 85.5 octane unleaded (elevation 5k')

Thanks all,
Justin

 

I don't think it is normal...mine was built in 07/05 and it gets a very rough idle. I am also having a hard starting/stalling issue. The truck is going in on Friday so I will let you know what they say about the idle.

Dave

 

yea, i just ran thru ownersite and checked TSB's on rough idle i didnt find anything in the 2005 model year, but when i checked 2004, i found two possible TSB's both listed 5/5/05 TSB 05417 and TSB 05515 if it is one of the above, can anyone tell me what the corrective measures are? yea, dave, i'm thinking somethings off- ive had no problems, no reflashes with my truck yet, so who knows.

good luck with your appt. on Friday

 

Take it to the dealer and have them check your injectors ASAP. I won't re-hash my story here, but just take my word for it.

 

hey tun2one, just read the injector saga, and the linked modular ford posts- what was your rough idle like, i mean, everything sounds fine- its just a subtle rumble/ruggedness just for a couple seconds like i said with 15-20 sec. of calm between each rough spell when at a light... did take it by the dealer earlier though to check my pcm dates/current codes, nothing has been logged, and running the most current versions- if you could give me a bit of background prior to the mangled engine, that would be sweet-
thx

on another note- the tech liked the sound of my engine, said it was quite a bit louder than the others he's driven, and his own- liked the power right off the line- even with the MT's on... (the dwv intake mod ) he asked me if i had done anything to it, or if I chipped it , said no, only thing is my intake- showed him the intake remodel- he was pretty impressed- thanks kd4crs!- , wrote down how i made mine, and said he was on his way to homedepot after his shift... )

 

Your description is exactly what mine was like. One of your injectors is probably hanging open too long, meaning that too much fuel is entering the cylinder, thereby causing it to run lean or rough. Since only one injector is faulty, the engine runs smooth until that particular injector fires again. Your dealer should be able to quickly check the injectors with no hassle, especially when you tell them you've read about how it can cause your engine to hydro-lock.

Also, test it on the highway. It may be very subtle, but can you feel it while cruising at 70 mph?

 

i'll test that out today...good idea-thanks man

 

Yeah mine does the same thing. Its weird, it will be smooth and then a couple seconds later it will start vibrating and be rough. And something under the hood rattles when it starts up. Kind of embarrassing for a 35,000 $ truck!

 

On the startup rattle, what oil and filter are you using? The required Silicone drainback valve in the filter is usually the problem. Fram and several others do not seem to do that valve correctly for the modular engines.
Chris

 

Took my truck in last week (04/04 build) for rough idle. I can't remember
the TSB number, but it called for PCM reflash and replacing the motor mounts.
Tech said new motor mounts were definately different. Idles smooth now!

 

ok, so maybe its not the idle? at 70, i cant tell if it does it or not, the toyos dont help the situation. but, it only does it when the truck is in 'D' when its in park, you cant hear or feel it. so i put it in D, put the parking brake on, and popped the hood.... maybe its the fan? you can hear the engine running, and you can hear the fan....its like the fan doesnt run smooth...refer to the first post where its smooooth, then gets rough, well when it gets rough, the sound of the fan gets deeper- i dont know. looking at the belts, you cant see any decrease in speed. you can definitely feel the truck shake though when its rough. let me know what you think- is it worth the hassel of service? thanks again for all the responses- Justin