Ford F-150 - 1997-2003 :: 1998 4.6L - Intermittent Misfire When Accelerate And At Idle
Jun 3, 2013
So my truck started to intermittently misfire about a month ago . I changed the spark plugs wires at first and it seemed to get better but it still had a misfire . I replaced the spark plugs and ignition coils and the misfire is still there . Up until the other day it was a noticeable issue but still drivable with . On my way home from work it got alot worse and started to misfire any time I tried to accelerate and now is noticeable at idle now as well.
I checked the fuel injectors resistance and they are about 14.8 ohms . I am not getting any codes for a misfire . I tried to pull the fuel injector connectors to try to find the source of the misfire but could noticeable change in engine rpm. Where to go from here and what I should check first? Would a clogged fuel filter cause something like this ?
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I have a 1998 f150 w/ the 4.6L V8
For months I have had a hesitation in this truck when i go to accelerate, and at times you can even feel a little buck with the cruise set at 70MPH. It has gotten worse and worse. When i start pulling a trailer good luck, it will do it but its terrible, hesitations and misfiring,
There is always a misfire/hesitation. Will Idle nice After its warmed up. Sat for 2 weeks fired it up and it had a HORRIBLE idle for at least 1-2 min. This is new now it wont idle when cold. Now I had one code Cylinder 4 misfire, cleared the code never came back 2-3k miles later still not back on -
replaced coil packs
New plugs
New wires
Fuel pressure test good
Checked the Heater hose - not leaking and nothing in the hole.
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Ford F150 1999 5.4 XLT... I've had this truck since may 2013 from the 2nd owner who only drove it
occasionally to make sure it ran. For the last 5 weeks there have been two occasions where my service engine light appeared...once on 12/28/15 and again today. Both read cylinder 4 misfire. Upon searching this piece which I'm assuming is the boot that covers or houses the spark plug is very unsecure and causes a shaking feeling as I accelerate or idle. Being so far back I can't reach it with extensions on a ratchet and barely fit my hand back there. Having to consider taking it into a shop for further analysis and repair but I'm trying to save as much money as possible as I am in between jobs since mid January. I have a picture attached...
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Ok I've been getting a intermittent misfire on my truck for soem time now. It ran great all winter but now its getting hotter it intermittently misses. Last summer I replaced all the coils. And the coil inquestion now was replaced since last summer with Motor Craft Coil. I have red the check Engine Codes a d here is the freeze Fram data
DTC :P0351
Fuel System I : Closed Loop
Calculated Load: 71.37%
Engine Coolent temp: 199.4 F
Short Term Fuel Trim Bank 1 : 3.91%
Long Term Fuel Trim Bank 1: 0.78%
Short term Fuel Trim Bank 2: 6.25%
Long Term Fuel Trim Bank 2: 0.78%
Engine RPM :1613.25
Vehicle Speed Sensor: 4.35 MPH
What might be my problem? Since The Short Tem Fuel trim from bank 1 and Bank two are vastly different could that mean my fuel injector is not working correctly?
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I have a 1998 F150 4.6 that has a misfire with no CEL. I have already tried the following: checked fuel pressure, change cam shaft sensors, changed coil, checked MAf seems ok, spark plugs and wires. On my scan tool it wont show any misfires when obviously its misfiring. When driving it will run good for about 10 seconds and then misses for about 10 seconds and it just keep going in this loop.
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I have a 99 F150 Lariat 4x4 with a 5.4, 150,000 mile on it. About 2 weeks ago I blew spark plug out on #2, and a friend who said he has heli-coiled a bunch of these tried to do mine and ruined the head. Anyway, I called a local engine shop and got another PI head, only I used my cam in it. Torqued it as per the book, etc... Mind you that the engine ran perfect before all this.
Got it back together with all new plugs, new exhaust manifold, and 2 new COP's. When I start it-it runs rough for about a min, then straightens back out to run perfect again, and after a few seconds you can hear a solenoid click, then it goes back to missing again. This goes on and on... I went through all the vacuum lines and checked them, checked the egr valve, put on a new IAC, new PVC, cleaned the MAF, and checked everything else with a DVM.
I took it out and drove it.... Runs good for a minute, then it goes back to missing, then back to smooth again. This just keeps going on and on. I noticed when I hear that click, it sounds like a mad rush of air being sucked in, but I cannot locate it. I ordered a new set of COP's to try next. I can understand if it just plain missed all the time, but this it intermittent. Also, the only code I can get is a too lean on bank 1, so I replaced the 90's and the pvc valve. Now no codes but still in and out of missing. It ran perfect before the new head.
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After/during the rain, every other time my truck loses considerable power to accelerate. It's not consistent but happens increasingly often. As I accelerate up to ~ 50km/h (also when I reverse), my engine will shake the entire truck. Past 50 it "appears" to go away. Typically this will last up to 10 mins and will disappear and run fine again. The last time it happened the check engine light came on and went away the next day. After reading online, I've heard about the "COP" connection??
2003 Ford F-150, 4.6L Triton V8 XL, 2WD
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1998 F150 4.6 automatic.
Had problems with battery light. Was intermittent. Battery cables wouldn't stay tight, replaced them, light stayed off. Light back on now, constant. Battery reads 12.5ish off, 14.3ish running under load (lights, AC, etc.).
When truck is started, even cold, it doesn't rev up the RPM's and then die down to idle speed. It just goes straight to around 550rpm and surges slightly up and down between there and 650ish. Can these be related?
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I have a 98 F150 4.2L with code P0301 Cylinder 1 Misfire.
This is what I have done so far. New plugs, coil pack, plug wires, TPS, EGR, EGR Vacuum control regualier, DMCP, canister, all of these parts are new and was bought from the ford place. Have taken the egr value, and egr value bracket off to see if carbon blockage was present, but it was clean. It was clean in the motor also. Have blown air through the metal tube that connects to the egr value and it come out the tail pipe very good, so no blockage their. Have cleaned throtle body and injectors. Have tested fuel injector with tester and it works correctly. Motor holder pressure. Have correct fuel pressure.
Do not have any vacuum leaks, it holds vacuum correctly. Crankshaft sensor is fine. Went throw 4 cans of break parts cleaner, spraying on intake while motor was running, motor did not idle up or change. I have done all this and it still shows code P0301, and it still skips. Here's the catch, if you unplug the vaccum off the egr the misfire goes away, or unplug the EGR vacuum control regulator it goes away, or if you unplug the DMCP sensor it goes away, it does not matter witch one you unplug, the misfire goes away.
I have had several different test done the the truck, but all the test only show that one code P0301, they do not show any other codes, or problem's with my truck.
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I'm a relatively new F150 owner (just got rid of the 98 Ranger I drove since 99), so I thought I'd check in to see if I was overlooking something obvious. A few days ago, after driving to the store with no obvious issues, I went shopping (coincidentally for oil change materials) and when I returned to my truck it would not start.
Here is a bit of info:
Starter cranks over the engine.
Battery is relatively new, and has plenty of power.
I can hear the fuel pump kick on briefly.
Check engine light is on (EGR Valve fault).
Engine started with starter fluid.
Engine ran like normal after starting.
Finally, the vehicle started/ran fine for a few days before the issue occurred again.
Like I said, I'm not too familiar with the vehicle yet, but I'm assuming the issue must be with the fuel delivery system. I plan on replacing the EGR valve, but I am curious whether a faulty EGR valve cause a no start? Also, I'm wondering if it's more likely that the fuel pump is going bad, or something electrical is the problem since I'm under the impression that the engine stops sending fuel to the cylinder if/when the engine doesn't start quickly after turning the key.
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P0306 (ok #6 missfire) with P0171 & P0174 --- Do I chase electrical or fuel or both. Afraid to assume anything but probably would normally address the misfire electrical first.... Don't want to go down that 'primrose path' if others have been there first!
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I got a 97 f150 4.2l from my neighbor. he takes good care of his vehicles. he sold it to me cuz it started to idle very rough like a misfire. it is hard to start when cold spits sputters and pops. once started idles like it wants to stall, then will idle normally then back to rough. back and forth like that. runs like a champ when going down the road . check engine light was on took it to auto store they checked codes . said bad o2 sensors so i changed them. still same issue. neighbor changed coil packs checked spark plugs and wire. every thing fires good. i changed iac. still didn't fix problem. could this be a bad egr valve or sensor? if so how can i diagnose this? he also thought was a clogged cat and bored it out. tight budget can't afford to take it to a mechanic. Was told spray carb cleaner spray around engine to check for leaks that did nothing at all...
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I have a 2001 F150 with the 4.6 engine. I get an intermittent drop in the idle from 700 RPM to about 500 RPM. The computer catches it quickly and brings the idle back up. It might drop several times and clear up or it might not happen at all. Seems only to happen on a hot engine, never when cold and in gear, if in park or neutral seems to idle ok. Changed the idle air control valve but no different. Runs fine except for the idle dropping when stopped.
Never get a check engine light, and no codes from the computer when I had it checked. Could this be the vapor management valve turning on?
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I was driving home last night and when I stopped at a light in town, I notice the oil pressure dropped and the light came on. So I pulled over and put in park to check my oil. As I put in park the pressure went back up. I dropped it back into gear and it went back down. What could be causing this? I check my oil and it was full. I also notice when I put it in gear and speed up the pressure goes back up and stays there till I slow down again.
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2000 5.4l lariat. My cylinder 1 for 2 years has been poping p0301code and has a rough idle at start for about 30 seconds. It also has a little white smoke for that 30seconds. new cop, new spark plug, new spark plug pig tail, swapped injectors to different cylinders multiple times to change code no luck. Compression dry and wet are at 200 and all cylinders are within10%. I had a dorman intake manifold installed 4 years ago and the code came a few years after. Im thinking intake manifold gasket is bad between cylinder 1 and the heater bypass tube allowing coolant to slowly leak down into the cylinder causing my rough start. I looked through the injector hole but could not tell. With all the info I have given is there any other places or things that it could be before I do a gasket replacement or is all my tests leading to the intake manifold gasket...
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My 2003 f150 5.4l has developed a slight stutter when I turn from a stop or go from reverse to drive or vise versa. I had thought it was the IAC so I replaced it but the issue is still there. There are no engine codes and it does not miss fire at idle or while driving. The problem appears to be happening only when the a/c is on. Could the belt be the cause?
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I have a 1998 Ford F150 4.6L Triton V8 with the FX4 package. As of recent I have noticed my truck tends to idle roughly every so often that I start it up and after longer trips but will run fine once I get going. I take care of my truck like its my baby. I've done everything to it that I can without getting into the engine such as replacing spark plugs, wires, KN air filter, new ignition coil packs, change oil every 5000 with best products, etc the basic tune up stuff every one should do. This truck only has 118,xxx miles on it as it sat in a barn for around 4 or 5 years due to the previous owner being in the military.
I have been trying to search for the cause of this problem but cannot exactly seem to pinpoint it myself. One unusual thing I've noticed also is that when I run the air either hot or cold when my RPM's get high, when I go up hills or punch it, the air switches from vent to dashboard(defrost). I talked to someone who said this was most likely a vacuum leak. Maybe there is a correlation between the two? I'm not exactly sure. I read online my idling problems may be from a cracked PCV elbow? I cleaned out the EGR valve also about two months ago to see if that work. I am willing to try anything myself as long as it doesn't involve tearing the motor apart!
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I have a 98 F150, 4.2 V-6, 183,000 miles.. Lately, she's been loping at idle. Especially while in gear... almost stalls. Once revved up, everything seems normal. Still goes up hills fine if I get on the gas. The light was on, and I got codes for lean condition on both banks.. (P0174, P0175).
I already cleaned all the sensors in front of the intake.
The MAF was real dirty, and the IAC was full of soot too.
They both cleaned up nicely, but it didn't work.
I borrowed a fuel pressure gauge yesterday, and it showed 12 psi with the "key on, engine off".
It showed 29-30 @ idle, and only went up to 35 when I revved it a little.
The guy at the store said the range is supposed to be "30-45 psi with the ignition on", but I'm not sure if that means engine running or not..?
Either way, it looks like the pressure is on the low side, so I'm going to change the fuel filter next (and hope for the best).
If the fuel filter doesn't fix it, what should I go after next? And, is there a way to test the fuel pressure regulator before buying a new one?
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My 2003 F150, 5.4L has been having some rough idle/misfires issues both at idle and under load.
I have fixed one big vacuum leak, replaced the PCV valve, new sparkplugs, seafoam and heet in the gas, replaced fuel filter, tested the fuel injector resistance. Coolant levels have not changed. The truck burns about a quart of oil every 1000 miles or so. The white exhaust is heavier than condensation, but it comes and goes. The rough idling comes and goes as well, and it usually happens under load and the CEL flashes.
The codes I get are random cylinders, po303, po308, po171, po174 were the most recent but there have been other cylinders as well. I clear the codes after each attempt to fix it and they come back different.
I notice that there is a small exhaust leak that drips water just behind the engine, and when I shut down the truck a lot of water will pour out of an area just behind the cab on the passenger side as well as out of the bottom of the muffler (small hole, looks drilled).
Usually the rough idle occurs after filling up the tank, but from different stations so I do not think it would be watery gas. I use Heet every fill up as well. Also, there is a sulfur smell after the rough idling occurs (catalytic converter?).
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Replaced the spark plugs and wires a couple months ago. Started skipping yesterday throwing the #4 misfire code so I replaced the coil pack, reset the check engine light but it's since came back on and has a rough idle and loss of power. By the way, it's a 97 F150 4.6L 4x4 with 200,000 miles.
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I bought a used Ranger a couple months ago and it ran fine when I test drove it but a week later it started having a misfire every now and then at idle.. I must have gotten pretty unlucky with the test drives..
The misfire comes and goes, it will run fine for a week or two and then it will misfire at idle for a week or two. It only seems to misfire at idle, the truck runs rough/shakes but once you give it a little gas and start moving it goes away. Usually it has a check engine light on from startup when it's misfiring and it goes away on days that it's running fine; it will occasionally misfire at idle with no check engine light. Sometimes when its running really rough the CEL flashes while it's misfiring at idle and I've actually restarted it real quick and the misfire went away for a bit. The engine codes that come up are misfire on startup and misfire on cylinder 4.
I've tried cleaning the MAF sensor, replacing the fuel filter, testing for spark and compression. Compression was 150-155 PSI on all cylinders, however, the compression on cylinder 4 is different depending on whether the truck is running well or not. When it's misfiring the compression on cyl. 4 is 90 PSI and when it's running fine it's 150 PSI. I'm not sure what could be causing intermittent low compression like that?
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