Ford F-150 (2004-2008) :: Vacuum Leak Causing Erratic Idle - Codes PO171 / 174?
Feb 3, 2011
I tugged on the little hose on the back pass. side of the engine,(5.4),...
and I could hear the vacuum leak that is apparently causing the erratic idle, and PO171 & PO174 to come up.
I know this hose is hooked to the Charge motion Control Valve on the back of the manifold,..I can't imagine what it does, as it terminates with some kind of plug or check valve??? Haynes say's to remove the entire manifold to get to the CMCV.
I can see it with a mirror,. I am thinking maybe long needle nose from Harbor freight,...bend the tip short,..maybe be able to change it out?????
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Can't find the PCV air inlet hose to the crankcase on a 5.4 3 valve V8 2006 F150. Most PCVs let air in on one bank and out the other bank on a V engine, but this engine has hoses going from BOTH banks valve covers to the intake manifold. The crankcase is under vacuum(8 inches vacuum at dipstick tube, 6 inches at each valve cover). There should be air flow in the crankcase not vacuum. No air is getting in which results in a vacuum in the crankcase.
Once the vacuum builds up enough after a few seconds when the engine is started the engine begins to whistle where air is being sucked in(can't figure out where) at a seal or gasket. If air could get in as it should there wouldn't be a vacuum in the crankcase and the engine wouldn't whistle. Where is the air inlet hose for the PCV system on the 5.4 3 valve V8? It must be clogged or blocked resulting in a vacuum. I can't find the hose and Alldata doesn't show it.
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So I was was tired of trying to tune my Holley 650 and finally threw in the towel and got a 600 Edelbrock. When the holley was on there the engine had the slightest surge but I was never able to pin down a vacuum leak. The PCV valve made quite the racket while running.
Now the edelbrock is on there and no matter what I did I could not get the idle below 750 (4 speed truck). I checked the carb, manifold, hoses, and boosters and no vacuum leaks. I disconnected the PCV port at the carb and plugged it and it immediately stalled.
I went down to the local speed shop and got a new PCV grommet that has a small opening (restricting) and some foam filter material in it. Got home and popped it in and the idle dropped right down to a near stall. Adjusted the screw and she's running fine.
Now for the question. Did I fix the problem or just band aid it? Has anyone heard of having to restrict the PCV circuit?
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I've read quite a bit in various threads about the large vacuum elbow collapsing, causing erratic idle speeds. My 2001 3.0 had that issue int he past. I shoved a 1/2" copper 45 degree elbow inside of the rubber elbow, and the problem was solved... until a few days ago.
We're now getting into the hot part of summer here. I've notice the same symptoms are beginning to return, once the engine compartment gets hot. My question is... is the large vacuum line a "hard line" all the rest of the way to the engine, or are there other places along it's length that can also collapse under vacuum?
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Long story short, I have a small vacuum leak in the 4wd system. I disconnected the lines going to the hubs to prevent grinding them to pieces as they are brand new. This, of course lock the front hubs in and disengages the X-fer case in 2wd.
It is not engaging in 4wd unless I select it, so I don't imagine it hurting anything in the X-fer case or anything. Other than the extra rolling mass, is this okay to operate at until I resolve my vacuum issue, provided I close all openings and places for trash to get in?
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I am having problems with a 2003 Ford F 150 with a 4.2 L V6. The problem is that it is giving me code errors that would indicate bad O2 sensors. I replaced both the upper and lower O2 sensors, and still I get the same codes. I was told by the mechanic with the computer reader that this usually means a bad vacuum seal. He suggested looking for bad hoses, but did not offer much more than that. How to proceed?
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I just purchased a 2005 elantra with 133k on it and she runs fine other than a slight erratic idle. And by slight I mean it will jump about 50-100 rpm idling and every blue moon it will jump up to 250 rpm sitting there. After idling for a while my CEL came on with the following codes.
P0507 idle air control rpm high
P0506 idle air control rpm low
P0170 fuel trim malfunction bank 1
P0121 throttle position sensor
What could be causing this? I took the iac off and cleaned it with maf cleaner but it didn't work.
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Just bought my volvo several days ago. It was throwing check engine codes so I had it scanned and it came down to a vacuum leak. I found the spot where it was leaking which was a little piece to the left and slightly behind the exhaust manifold, slightly behind and beneath the thermostat housing. It went from a hard plastic vacuum line, to a 1.5 inch rubber vacuum line which plugged into a nipple on the exhaust manifold or something behind the manifold. the rubber section had 3 large holes in it, so i replaced it with more rubber vacuum line. same length and same inner diameter.
What I did notice when I replaced it was that it was too large for the plastic line, slid on way too easy, but i had to fight it onto the nipple. The check engine codes went away for 2 days(I drove about 150 miles over that time) but today, the check engine light came back on, went to auto zone, had them scan it, came back with vacuum leak. So when I got home, I popped the hood, sprayed some carb cleaner by the replacement vacuum job I did, and sure enough the idle changed. What the proper replacement hose is for that area?
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My wifes 2008 Eddie Bauer Explorer V-6 recently started having an erratic idle and we've started noticing it while at higher RPM's. Its almost as if there is a cylinder that misfires but no engine light is coming on. The car stumbles like it is going to start to die, then the idle jumps up and smooths out. A little while later it does the same thing. The car has I think 74,000 miles on it and has never had the plugs or wires changed. I change out the fuel filter roughly every 24,000 miles and did it recently in the spring. Any places where I should start looking? Could a misfire not trigger the check engine light?
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I have late 2004 with 130k with a bpd egr cooler and new oil cooler and new ficm from Ed. Cat delete with no muffler. Everything else is stock I have a dash boss and was noticing some weird numbers. My check engine light came on but I couldn't get any codes with the dashboss. I started monitoring the egr error and saw some erratic readings really high negative numbers after I let the throttle off. The truck runs okay but was kinda starting slow. Could my egr valve be stuck? Could my short modified exhaust be messing things up?
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I bought a 04 FX-4 a couple months ago with 102k on it. Brought it back to selling dealer, they replaced #1/#6 coils, its ran great till this past week. Again it has stumbled a couple times this week. It only seems to have the miss at idle (comes and goes) take off from light, within 50 feet its running like a champ again. I cleared the codes (disconnect battery)and now it seems my idle is not steady, it fluctuates. Is the idle a product of the codes?
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I just received a 06 F150xl with a 5.4 triton and idles rough with the following codes! p0357 p0012 p0340 p0344 p0351 p0352 p0356 p0358 p0357 p0102 p0113 p0353 p0354 p0355 It's amazing the truck even runs and with no light on but it will accelerate. someone mentioned to clear the codes and drive it 50miles or so and read them again.
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For the techs in here, I have a data logger (AutoTap) and the symptoms are low idle and sometimes it runs rough idling and driving. It had me thinking the fuel pump was going out. That is not the case. I did get into part swapping mode so I have new plugs and coils and new VCTs all in the last 24 hours. The engine has 85K miles on it (rebuilt ford long block), truck had 150K. I'm not sure what parts were replaced when the longblock was replaced but I'm guessing the 02's are original.
Data that looks odd to me in the Autotap real time data logging is this:
- STFT Bank 2, goes from 10-15% and climbs till its over 300% and then the truck goes into Open Loop due to an error (per the Autotap) but it never says what error and the CEL never lights. Idle goes up when its in open loop and then after a minute or two it will drop back into closed loop.
- Fuel pressure never drops below 37
- Idle will drop to 250rpm
- Engine load at idle is 25%?! With AC on and idling (at 550rpm) engine load is 42%? Seems high no?
Nothing else other than the STFT Bank 2 and the high engine load seems out of miss. No misfires, codes, etc. What else should I look at?
Other background/patient history:
- Alternator #3 was installed 2 weeks, It replaced alternator #2 that went in 4 months ago to replace the original alternator (144K miles). Both died and caused low voltage/battery dying symptoms and verified by volt meter.
- FPDM was replaced proactively 8 months ago just because I don't want it to break down when I'm towing my race car.
- I have not tried cleaning MAF, EGR?, IAC, nor have I replaced O2s. The only thing that leads me to believe MAF might need cleaning is the load?
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My 2004 f150 has always been great to me. all the way till now at 255k miles. My truck is misfiring really bad. Here are the codes I have :
P0506 low idle (because of the misfire)
P0356 ignition coil F (6) primary/ secondary circuit
P0308 Cylinder 8 misfire
P0174 system too lean (Bank 2, right side of engine)
p0316 misfire detected on startup
This problem happened 2 days ago. I reset the codes and they all come back together in 10 minutes. the misfire is very bad. I wonder why coil 6 has a fault code but number 8 has the misfire code.
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5.4 3v. my last few weeks have not made me a fan. Here are the details:
I bought a 2008 F150 XL 5.4 3v with a cam phaser knock. Have done other timing jobs in past with no trouble so I was not too afraid to tackle this one. famous last words...opened the motor (shout out to the passenger side valve cover and its designer here) and found semi damaged roller follower on driver side. Worn cam lobe on the corresponding lobe and a loose chain on passenger side. proceeded to :
Change all timing components: phasers, chains, tensioners crank sprocket, all applicable bolts and BOTH cams as well as all lash adjusters and roller followers. most looked fine in fact all really did with a bit of wear on a few roller followers but only one bad one. engine didn't look to bad pretty clean.
Double and triple checked my timing chains and it was spot on. dark link on spot on crank, two dark links on the L and R dead on. put it back together. oh yes, changed all plugs with motorcraft ones, didn't even break one. did not change vct solenoids because I falsely assumed I could change the later easily if needed. they looked ok. screens intact etc... silly me for not realizing how kind Ford was in 2007 and later to necessitate removal of valve cover. I was reading a previous one on the how tos and assumed later models would be the same since it was the same sensor...
Cranked truck ran great. I mean perfect. sounded perfect. ran like a scalded cat. till it got to hot idle then it started doing its thing. rattle shake till you revved it. ran fine just wouldn't hot idle fine especially in reverse or under slight load. replaced driver side vct since ford only had one and I started on the easy side ordered the other one waiting for it. seemed to improve dramatically meanwhile I am driving this truck to test it. I drove it to work 50 miles each way and it ran great.
After a few trips it popped the P0420 light, seemed to run ok, cleared it watched it wouldn't come back. O2 sensor did seem to imply a bad cat on bank 1 since it seemed sensor two was mimicking sensor one and not staying stead like the other bank. still ran fine,
So I decided to check back pressure on the cat. I pulled sensor one out of bank one (really a joyously tight squeeze in there) hooked up my gauge and got 0 back pressure. revved it and all nothing. hooked sensor back up pulled truck out of shop and it commenced to running like crap. I mean bad. running worse than before I got it. Popping P0012 code continuously, and tons of misfire codes associated with bank 1 ..cyl 3 etc.. I tried swapping coils, pulled coils and checked spark with a tester and firing away looks like tons of good spark.
Now the weird part is : looks like bank one is dead. I can unhook any coil pack and/or injector and it runs the same and sounds like it is missing. if I unhook one off of bank 2 it almost dies or does. so bank 2 seems to be running fine. it will start and run but sounds like it missing sets flashing check engine light and backfires and stalls like crazy. I even second guessed my pressure gauge and unhooked exhaust manifold from pipe and it sounds even prettier when it backfires out of there but no change. I pulled cam sensors and cleaned it again and even tried swapping them since they looked identical but no change so I put them back.
Now I can only surmise that I am out of time somehow? or I have a gremlin perhaps? I like working on cars (usually) but this one is getting old. how do I verify what is wrong. if it is timing related how do I verify that now definitively once my marks moved I really cant figure out how to tell if it is in time? Since it has all new parts and they all ran beautifully till now. could it possibly be the vct solenoid doing all this? I plan on changing it when it comes in but surely it cant cause this many problems.. I unhooked it no change, and it does it at a cold idle and any rpm. really runs worse at idle but bad at any rpm.
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I recently purchased a Ford pickup. I bought a 2004 F-150 with the 5.4L 3V engine. I have only driven it for about 300 miles so far and am having problems. The engine has 200,000 miles on it. I have read several posts on here about the cam phasers which I believe that I may have some issues with. The engine will run good when cold, on the road, etc. The engine does have a slight ticking after it warms up (cam phasers?). When I come to a stop after the engine is operating temperature, the engine will start to miss and shudder and all 4 above codes come active and are also pending (8 codes in total).
All 4 codes are logged at the same time. I have replaced both cam position sensors, both sensor ends and terminals for cam position sensors, checked wiring around rear of engine (does not appear to be rubbed through), all plugs were replaced, and all COP boots are good. Is there anything that can cause these codes that may not be the actual cam position sensors, ie. VTC, COPs, cam phasers? What pins the cam position sensors come to on the ECU (so I can ohm the entire wire harness)?
Also, if the engine is missing with the codes active and I rev the engine up it will come back to idle and run great. The engine never dies out, just runs horribly. I have also unplugged each sensor with the engine running which has no effect on the way it runs.
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I recently purchased my first Ford pickup. I bought a 2006 F-150 with the 5.4L 3V engine. I have only driven it for about 300 miles so far and am having problems. The engine has 146,000 miles on it. I have read several posts on here about the cam phasers which I believe that I may have some issues with. The engine will run well when cold, on the road, etc. The engine does have a slight ticking after it warms up (cam phasers?). When I come to a stop after the engine is operating temperature, the engine will start to miss and shudder and all 4 above codes come active and are also pending (8 codes in total).
All 4 codes are logged at the same time. I have replaced both cam position sensors, both sensor ends and terminals for cam position sensors, checked wiring around the rear of engine (does not appear to be rubbed through), all plugs were replaced, and all COP boots are good. Is there anything that can cause these codes that may not be the actual cam position sensors, ie. VTC, COPs, cam phasers? What pins the cam position sensors come on the ECU (so I can ohm the entire wire harness)?
Also, if the engine is missing with the codes active and I rev the engine up it will come back to idle and run great. The engine never dies out, just runs horribly. I have also unplugged each sensor with the engine running which has no effect on the way it runs.
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Everything started with the typical lean bank 1 and bank 2 codes. I started at the basics change fuel filter PCV Hose & Valve clean the MAF changed air temp sensor(it was cheap). Still had same po171&po174 codes. Bought a obdll reader. After 3 weeks of nothing being accomplished I bit the bullet and took it to Ford for a diagnostic and they said it was definitely the intake gaskets.
I changed the gaskets and now this has gotten worse! I started the truck after reassembly and it ran like crap!
Checked everything and everywhere and could find nothing wrong. I then took off the vacuum line to the EGR and everything smoothed out. I didn't mess around and replaced the EGR the DPFE and the vacuum solenoid.
It still runs like crap especially at idle. I did the tests with my digital meter and found the vacuum solenoid is calling the EGR to be open all the time. I suspect that this would be the fault of the PCM? What should be my next course of action?
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I am working on a 2003 toyota matrix 1zz-fe automatic.
Replaced engine ran good for 20 miles, rough idle as if vacuum leak but no vacuum leaks to be found. If I disconnect and plug the vacuum hose that pulls from the air intake is smooths out and runs good.
Some reading suggests that it is the idle air control any?
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2002 F150 5.4 v8,,, I had troubles just over a month ago with a po305 code. i got the truck fixed with 2 new coils n some gaskets. I am having these po353 & po171 codes pop up now. The truck is running rough and I am curious to if its just another coil problem or if their is something I am overlooking or just don't know about?
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I have an 05 F150. Last week engine started running rough, check light was flashing. Engine lost power and got more erratic. Had it towed to Ford dealer, Dickson TN. Dealer says "#2 injector has suck open and flooded the Cylinder and bent the C-Rod." Ok have put in another 5.4(not at Dealership) hummm new engine runs the same as the one that came out. Had A different Dealer check this engine they tell me the right bank is not making compression cam has jumped time.
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