Ford F-150 - 1997-2003 :: P0401 Code / Occasionally Missing Under Load
Jun 6, 2014
Have a p0401 code which I need to diagnose and solve. However, I don't believe the symptoms are indicative of the EGR system. Its a 1999 4.6L auto approximately 200k miles. Truck runs fine until it warms up, and then occasionally it begins to act like its missing under load. steady state on the freeway it may have an occasional miss, but put a load on the motor and the miss becomes real bad. This doesn't seem to me to be symptomatic of a P0401 code, but I don't really understand the EGR system enough to be sure. Searching on the forums for other p0401 codes doesn't seem to have the same symptoms.
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My 4.2 liter F150 suddenly started missing under load. A little background: It is a late 2003 and has 75k miles. It has been in my family since new, and I have had it for the last 4 years. This truck is as stock as they come, and has been well maintained.
On my way to work yesterday, it began missing. Not bad at first, but got worse. It misses while under load and under acceleration. The "check engine light" never came on. I have not put fuel in in several days, and it ran fine until now, so I doubt it is bad fuel. I started the engine after dark and looked for arcing. None visible, and I even sprayed the wires with a mist of water. I pulled the plugs and they all look normal. The gaps were all way too large, so I regapped the plugs to .054". I pulled the coil pack and it checks within range with my VOM. Can the coil pack be the problem even though it checks out on the bench? Can the large plug gaps have contributed to a coil pack failure?
Where to start. I HATE just throwing parts at this thing, and I don't like wasting money... If I let one of the auto parts stores run a scan, will it show a code even though I have no check engine light? I used to think of myself as a pretty good diagnostician, but then again, when I used to spend a lot of time under the hood, those cars had points, condensers and carburetors...
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So here's the background. I recently bought this truck. It's a 97 Ford f150 4x4 4.6l 99w vin code. Anyway Driving it home got a p0401. No problem. I Applied vacuum from other vacuum source to EGR engine stalls. So to me passages are clean in the throttle body. I checked to verify and indeed passages are clean. No while doing so I noticed no vacuum was making its way to the dose valve thing. Strange.... So took the line that runs to the passenger fender to dose off and it was impossible to blow air through.
So I cut out the clogged section found solder in the line. I filled the gap I now created using some 5/32 vacuum line reconnected to test and to my anvil still not vacuum. So I disconnected it again. Went directly to where the yellow/orange dose vacuum line connects to at the passenger fender and to my surprise no vacuum there either. No my question is. Am i suppose to have constant vacuum to the dpse or I'm I just being an idiot. And two if I am suppose to when the vacuum line runs into the passange fender where does it go from there and could I have a major issue in my hands?
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On my 98' f250 4.6L 4x4 .. My check engine keeps going off and on, I finally pulled the code and its the P0401. The truck pings and knocks now and than and idles a tiny bit rough sometimes but overall runs good and gets the same mpg it always gets.....is this a bad egr valve?
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I've had a 0401 code on my truck for the last two years. I've replaced the EGR valve and the dpfe sensor a couple of times, with fomoco parts. Ive also cleaned out the egr tube that comes off the exhaust manifold. In this time I also discovered a couple of vacuum leaks and replaced those. I changed the pcv valve, tried running 93 octane gas, and had a mechanic friend run a special smoke through the vacuum lines to find more leaks. Also put a brand new gas cap. I have an obd computer and cleared the code repeatedly but the light always returns.
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My 2001 F-150 came up with this code and I changed the EGR valve cleared the code and it returned 15 miles later. The truck only has 30K miles and the warranty expired 24 May.
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Dreaded insufficient EGR flow. I've read I should clean the EGR ports.
I can't really find where these are? I took the throttle body off.
What I should do with this thing? I also get a hesitation on initial take off.
1999 F150 4.2 V6 ... 160k miles on it. Runs good otherwise.
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Has a P0401 code EGR unSufficient flow. Ive read several things that it could be, from a DPFE sensor to the EGR valve it's self our that the port going into the TB could be plugged. Truck drives fine does not have a miss or anything noticeable when driving other than the CEL, trucks a 4.6 with 200k on it. Forgot to mention it sometimes gets a P0455 code but i assumed that is gas cap. or could it be related?
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I have a p0401 generic exhaust gas recirculation flow insufficant detected code on my truck I was wondering what would be the first thing to check to get ride of this code? my truck hesitates from a stop while excelerating to several thousand rpm. should I try replacing the dpfe sensor? what does dpfe stand for? do they sell this sensor at oreilys or do you half to get this a the dealership?
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97 4.6.. So it would appear that I have the wild goose chase of codes. The major symptoms are rough idle and very poor performance. I started off by cleaning the egr valve and ports. Then I checked the egr valve itself and watched the valve open and close under a vacuum. I was suspecting the DPFE sensor but I wanted to trying something else first. I was under the Impression that if at idle you apply a vacuum to the egr valve it would cause the engine to "stumble and stall". I did this and there was no change in the way the engine was running. So now I'm lost as to where to go from here.
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I have a 97 F150, 2wd, 4.6, auto bought for a great price agout 3 months ago.... I installed a cold air intake (air raid) and a throttle body spacer with the swirling cuts.
Since the cold air intake add, the truck occasionally makes a load "roaring" sound from the intake system. At same time rpms increase 500-1000 rpms...
it doesn't do it all the time, mostly at low throttle, and a quick jab on the accelerator usually stops it. sometimes such as when parking, holding the brake and applying a bit of throttle with load from the brake will also stop it.
Guys at local garage seem to think it has something to do with lower outside temps, (denser) and addition of cold air intake. it made the noise before the throttle body spacer.
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I have a 2000 f150 with 5.4 Triton with 165k miles. I did invest in a code reader. It started missing and code P0302 came up along with P0171. Put new coil on #2 and truck ran fine for a few days. Then it started to run rough again. Shaking, Idle rough, no power and CEL came on again. This time code P0171. I changed out fuel filter to no avail. My next step was to start looking for vacuum leaks. As I'm searching, All I am finding is trucks with this problem also get P0174 code. My question is since I am only getting lean on one bank does that pretty much eliminate things like MAF or the famous elbow vacuum leak and make something that only affects one bank like an O2 sensor on CAT more likely?
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My truck, the aforementioned 01 f150 5.4 has been running fine but has had the codes p0401 and p1740. I know what they both mean I just haven't fixed them yet. Today I went to move my truck and it wouldnt start. It turned over fine and would hit some but wouldn't start. Would the tcc solenoid be the cause of that? Also the reason my egr is throwing is because there is a line that is not connected but I have no clue where it connects to... Where is the best place to get diagrams for the egr system.
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This is what I have done I have 5.4 168,000 on motor . I have codes p0401 p0701 p0704 and some others .I can run truck for about 15min and it starts to lose power .I can't go over 1500 rpm . I have changed egr cleaned throttle body checked for vacum leaks changed the dpfe . new plugs . I have had a misfire code on number 1 but that code has stopped . I have put new fuel filter .I have a cheap scanner I use and it probably won't give me what I want also I changed down stream 02 sensors .
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My 97 F150 4.6 4x4 threw a P0302 and P0401 the other day, I traced the miss fire to a loose injector plug. I reset the codes last weekend, I got in the truck and went to the Dump and to town to pick some stuff up. It threw the EGR code again, so this morning I did a little checking on the EGR I cranked the truck and disconnected the FPR vacuum line and hooked it to the EGR valve and the truck died down but didn't completely die.
Now the green line that went to the EGR valve felt like it had a slight bit of pressure coming from it. Is this normal? I did pull the white feed line from the EGR Regulator and it had good vacuum.
The regulator also makes a humming sound when you cut the truck off. Ill be pulling the alternator this weekend due to it going out last night, while I'm in there if Ive got to pull the throttle body id rather do it while I'm elbow deep in it. So does it sound more like a Clogged Throttle body or a Faulty sensor?
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I just bought a 2003 F250 from a used dealer. Unfortunately the service engine light keeps popping on and putting out the code P0401, I have replaced the EGR, cleaned the inside, and cleared the code. However it continues to keep popping up and then it will turn off after a couple of days. I mostly drive in the city and the code generally only pops on when I drive on the highway. I have also noticed a lack or delay of power, when I really hit it hard, I think its because the computer is keeping the egr valve open. What it could be?
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1994 f250 7.3 turbo problem.. runs great on the level.. Cruises 65 no problem.. We have an 8% grade coming from town and half way up it starts cutting out and sounds like a jack brake under the hood and loses power.. Once over the top it clears out and runs fine again.... I just changed the fuel filters but no luck... I have been wrenching on cars all my life but no diesels..
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A friend from work is having what he says is piston slap, but only under a load. I feel it could be the timing set since it's never been changed and at least 160k miles. Odometer quit working at least 5 years ago. Other than that, motor runs great. 1997 F150 4.6....
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it's missing at an idle and it acts like it dont wanna take gas but once you get it going on the road it does good. the motor is a remanufacture motor it's only got 6,000 miles, new coils, plugs and wires, cam sensor, crank sensor, idle air control, mass air flow,and temp switch.
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So today, I planned on switching the belt, idler pulley and tensioner since at least two of them are making noises. After taking all of the stuff off, belt, idler pulley and tensioner... and since I always compare parts I buy to parts that were in, making sure they are identical and I didn't order the wrong one. So first up I checked my tensioner and the position of them or angles are different, completely different.
So Google it to view a few diagrams and bang! it hits me... the one I took out from my F150 is for a non-AC... so back into the truck and I'm looking. Didn't have to go far when I realized that my AC compressor is missing!!!!
I keep looking around and I see that yes, I did have AC in it before I got it; because the guts are there but sliced! Great, so the job went from easy and easy I mean buy compressor and install; but now since the guts were cut, the PO sliced the thing out simply put.
1.) What are the bolt sizes that hold the compressor in place?
2.) Is there a wire connector on the compressor? or no?
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It has been since the 80's that I have attempted to do any work on a vehicle. How do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents. I have an 2000 F150 with the large engine with about 112,000 miles.
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