When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Oh I see now. Mine is bonded to the plastic piece there at the red arrow instead of A clamp. Now I'm doing research to see if my dip stick tube leaking smoke will effect or cause my rough idle.
Oh I see now. Mine is bonded to the plastic piece there at the red arrow instead of A clamp. Now I'm doing research to see if my dip stick tube leaking smoke will effect or cause my rough idle.
Actually, you now have three vacuum leaks:
>The PCV fresh air tube (see green tab)
>The leak at the MAF connector
>The dip stick tube.
Each leak may be small, but combined they may be significant.
Oh geez that means I have A vacuum leak around the oil pan gasket too It is actually leaking oil around the oil pan I hope it isn't the rear main seal. And you tube videos are showing tons of these dip stick tubes breaking off while trying to remove them. Wow what A mess.
On the bright side, I put RTV silicone around the MAF grommet and the vent tube. I went for A drive after the RTV dried and smooth idle, however after I got home and went to back in my driveway the truck is shaking again while in park or neutral. Shaking at idle goes away when I put truck in reverse or drive. Also smooth out in park and pressing gas petal to maybe 800 to 1000 rpm.
Try looking at the trans codes and live data. I know it’s different, but I had that on a Chevy. Trans wouldn’t disengage fully because of bad solenoids and caused rough idle.
Was there ever any resolution to this? I have been fighting this with my Dads 2008 F150 4.6 for awhile. All plugs and coils have been replaced and I have checked for vacuum leaks. Tonight I am changing out the EGR as a hail mary fix. Truck has 83k miles on it and has been this way for a long time. He doesn't mind it but every time I drive or ride in it I tell him I have to figure it out! Also fuel filter was changed and the MAF sensor is clean.
Never got it resolved. I sold the sob got tired of fighting with it. Plus when I dropped the gas tank to see if A new fuel pump would fix it, I noticed the frame rusted all the way through behind the tank. So all that work, and money for new parts for nothing.
The plugs and coils were replaced last year with no change to the rough idle. I replaced the EGR and while I really think it runs better for some reason, the idle still isn't smooth. It doesn't do it until it's warmed up. When it's cold it isles fine.
MOD NOTE: Quoted post from a spammer removed.
Last edited by 85e150; Mar 22, 2023 at 06:49 PM.
Reason: spammer removal
The codes aren’t any help - the PSP and brake switch codes are most likely operator error (the steering wheel needs to turned 1/2 a revolution and released and the brake pedal applied during the KOER test), the P1000 just means the truck has to be driven a certain way to enable all the monitors (more for emissions inspection) and the OCS is related the airbag system and won’t affect driveability.
Here are general specs (not Ford specific) on live data once the engine is in closed loop, at operating temp and at idle:
MAF - At least one gram/second per liter of engine
Upstream O2 - Switches consistently from rich to lean - if your scan tool has a graphing function this will be much easier to monitor
Downstream O2 - Steady, constant voltage with little variation
Short term Fuel trim - Technically anything in the range of -25% to +25% is considered normal, but realistically, less than 5% is what you want to see - don’t worry too much about the long term at this point. The LTFT is used by the PCM to adjust over time - not that it can never be useful, but in terms of diagnosis, STFT is what you want to watch.
MAP - Reflects Engine vacuum (minimum 15 in*Hg but I can’t recall if it will read out as in*Hg or just as negative PSI)
In my experience the most common cause of a rough idle is a vacuum leak. I understand you just did an intake reseal but that doesn’t mean all the vacuum operated controls and accessories are in good order.
I recommend unhooking all vacuum lines and capping them off to see if the idle smoothes out. If so, hook them back up one at a time and observe the effects - if one causes the engine to start stumbling, you found a leak. If not, you need to focus on engine controls.
Check the DPFE sensor voltage as well (I’ll have to double check the correct voltage at idle) - the EGR might be stuck open.
very nice you took the time to write this. I need to save this thread.
I have been battling all summer to clear up my rough idle and low end loss of power ( truck comes to life at about 2000 rpm in passing gear). Rough idle goes away at about 1000 rpm. 2006 F-150 4.6 two valve 4x4 4r70w auto transmission. I attached some stored codes and data pictures. I don't know what the mass airflow, oxygen sensors, short term and long term fuel trims are supposed to be on my truck. No check engine light lit up. I have replaced all plugs, coil packs, and throttle body. All Motorcraft parts. New EGR assembly from Napa. New Plenum and intake manifold gasket set Fel-Pro. Please let me know if my fuel trim, mass airflow, and all four oxygen sensors data is within speck. What could to problem with my truck be?
Blew the head gasket recently, tore down to repair, #1 piston had hydro locked and bent the rod, would only rotate crank 180% to a dead stop, initially I found every connecting rod and piston with bearings and rings had different weight outs, some off by a few grams,
it may be a pain but it may be easier just to purchase new crankshaft assembly and bearings and replace them all, that way everything can be properly weighed and balanced.
Gunna have to do the same to mine apparently, after reading all through this forum and others it appears I may have the same leaks and or unbalanced rotation assembly and rough idle! When she's up in the rpms it's fine but essentially I think the bottom end needs new seals bearings and clearances checked
Last edited by Shores D; Jan 19, 2025 at 12:20 PM.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
It is actually leaking oil around the oil pan I hope it isn't the rear main seal. And you tube videos are showing tons of these dip stick tubes breaking off while trying to remove them. Wow what A mess. 
