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.
View 8 RepliesI 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.
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.
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 ?
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!
View 4 RepliesI have a 03 F150 with a bi-fuel 5.4 engine an it has 195000 miles. I have had trouble for some time now with misfires. I bought the truck in october of 2011 with 125000 miles and replaced all the coils and spark plugs because it was misfiring badly will running on CNG. It was fine on gasoline and never had any codes. After I replaced the plugs and coils it ran fine on CNG and gasoline.
This summer 2013 it began missing badly at highway speeds only when running on CNG. If I accelerated the miss would go away until I was light on the throttle again.I checked the misfire count and found the bad cylinder and replaced a coil. Then a day later same thing on another cylinder. I swapped a coil from another cylinder and problem went away for a day. Eventually I chased the misfire around all the cylinders on the engine until I had ended up either replacing a spark plug or swapping a coil on all the cylinders. And I still had a misfire. It seemed to be worse on days with temperatures above 90 degrees. Eventually I got it to stop misfiring.
So now 5 months later I am back again with a misfire. This time it is misfiring on both gasoline and CNG and under any throttle conditions, except coasting. I have no codes. And the misfire monitor is sending me around the engine again. I have replaced a spark plug in two cylinders and swapped 4 coils.
I'm ready to buy all new coils, but I want to be sure that it is not a waste of money since the old ones only have 70000 miles on them.
Two days ago I had the misfire monitor saying #4 in the evening and the next day without me having done any work on it it was saying #6. Later that same day it said #7 and I still hadn't done anything other than drive the truck.
I checked the connections at the firewall on the drivers side with the three large plugs that are held in with a 10mm bolt, they looked fine, no corrosion or burnt pins. I checked the connection at the ACFM which also looks good. I will check the connection at the PCM in the next day or so.
Some other problems that may be contributing:
1. I occasionally get a U1262 code (scp fault)
2. Sometimes when I check the misfire monitor it only shows 7 cylinders, sometime 9 cylinders. I am using an Innova 3160 scanner.
3. I have either a leaking valve cover gasket or leaking head gasket, because I have oil dripping from the rear bottom corner of the passenger side cylinder head right above the exhaust pipe.
My 97 F-150 has 208,000 miles on the original engine. It started misfiring originally on just 2 cylinders, 1 and 8, after pulling the codes. I also get a P0420, catalyst system below threshhold bank code being thrown, but I think it is because of the misfires.
To remedy this I've done the following:
1. Spark plugs are relatively new and were changed completely a few months prior to issues.
2. Coil Packs were changed on both sides. Additionally, Cylinders 1 and 8 are on separate coil packs.
3. Spark Plug wires were changed
4. Did a resistance test on each fuel injector and they all passed.
None of this has worked. Am I missing something obvious? From my friends I've heard everything from my exhaust is plugged to I need to change all my injectors. Injectors are costly and I'm not even sure how to check if my exhaust is partially plugged, but it seemed to be flowing fine. Also, I pulled plug one since it was simple to get to and noticed it was slightly brown, like it had oil on it.
I got frustrated and continued driving my truck until the problem degenerated into severe misfiring and now I cannot get it started at all (Wrong move). I bought a car and haven't drove it since, and have it sitting behind my house. Now the cops want to tow it because the registration is has expired so I've decided to move it into my garage so I can work on it. Part of me wants to junk it, but I've put a lot of time, money, blood, sweat, tears, and curse words into this truck and am motivated to get it back up and running since the transmission and front suspension had been replaced recently.
What to do!?!?
1. Go to the Ford dealership and have them diagnose the issue and then try to fix it? (I have little confidence in them from the stories I've heard)
2. Pull the engine, tear it apart, and rebuild it?
3. Drop a used/rebuilt engine in?
4. Call me crazy and say junk the truck and buy a different one?
Currently leaning towards option 3...
I have changed the COP and the injector as well as the spark plug. I am still having a misfire on #7 cylinder....
View 8 Replies97 f250 5.4 L ............. In the torque app main screen hit menu, hit settings ,scroll down to manage extra PIDs/Sensors ,hit menu again , add predetermined set and I choose Ford (including power stroke ) ,now you see a big list of things you can test live ,hit cylinder misfire (whatever cylinder # you like to see) scroll down and hit test ... well you will see on the top results a live misfire count data constantly updating ....I know because I disconnected COP #1( it took 1-2 mins and started counting) ...
View 3 RepliesTruck has been running rough and the check engine light was on so I decided to get the codes read and I got back P0302 and P0304, which from what I understand is a misfire on cylinders 3 & 4. At the same time I got Ford to do a little diagnostic and this is what they wrote for me:
"The connector for the number 2 coil is broken and will not stay plugged on to the coil and the number 2 coil is not working / replaced the wire for the coil still running rough removed the coil and plug. the plug was very badly fuel soaked started the vehicle to see if there was spark at the plug. OK. Suspect either a injector issue or a compression issue cleaned the plug seems better. "
So of course they quoted me for the works. They say I should replace the coils, plugs, and injectors???
I am pretty mechanically inclined and think I could change these things myself since I am on a budget. One tech told me is that the plugs can seize in these engines often and could scrap the whole thing??? Seems a little weird. If that happens though what could I do?
My truck has developed a misfire on cylinders 1 and 5. The OBD2 scanner at autozone says code P0300, Po301 and P0305. I bought a new set of plugs and wires. Problem still there. I then replaced the both coils. Problem is still there. Is there a control module or something that could kill those 2 cylinders like on the older trucks with distributors?
View 7 RepliesI 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...
View 14 RepliesI have a 1997 F-150 2WD 4.6L V-8 that began having random misfires as I would drive. I was planning on going out today to get the new plugs and coils however when I got off work and pulled into my drive something happened when I went to leave the truck wouldn't even crank it just made a clicking noise. The battery has full power (the radio ect. still works). I am hoping that the problem is with the coils and plugs but if not ...
View 5 RepliesI have a 2002 f150 5.4L 4x4 7700 and she was misfiring bad the other day I changed coil pack 1 and 4 because that's what my codes where reading and i changed all of my spark plugs just because the check engine light went away for a little over a day and boy was she running good she had a little hiccup with a misfire but it quickly fixed itself but later now my check engine light is back on and is miss firing again and this time it isnt fixing itself what is going on with my truck?
View 8 RepliesI have 97 150 it has a misfire on cylinder 4 and 6. I put new coil packs on and new plug wires. Spark plugs are only a year old. what else it could be?
View 1 RepliesI started out with misfires in cylinders 1 and 7. Replaced all spark plugs (used autolites, i know i know). While replacing them I found that the boot on coil 8 was beat up with a chunk missing. It was working before I replaced plugs. After I changed everything out the 8th quit working completely and I still had a miss in cylinder 1.
Replaced coils on both of those and put a new wire connector on for 8th cylinder because it no longer clicked in correctly anymore. Truck runs infinitely better than it did prior to this, but according to OBD2 I still have misfires in 1 and 8.
Mostly in the 50-60mph range. What else could be causing this??? Injector maybe or is there some other sensor or timing problem? My dad has a compression test kit, but he lives several hours away so I can't just get to that right away.
I have an 01 5.4 Triton with engine light on I put it on the scanner and it read miss fire on cylinder 6 and 1 I changed the cops and plugs boots and spring erased the codes but the check light is back on and scanner is say miss fire on same two cylinders u can hear it in the exhaust u can smell gas when sitting at an idle around 40 MPH has a slight engine shake goes away when u accelerate I am not sure what else to do some one told me to check for vac leaks and fuel pressure.
View 14 RepliesSo my 99 F-150, 4.2L started throwing a code a few weeks ago, P0306 #6 Cyl Misfire. This thing has got 238,000 and has been the most reliable commute vehicle I've owned.
Today I changed all the plugs and wires (they were due anyways) which didn't resolve the issue. After clearing the code, got about 3 miles out and it came back. Running SeaFoam through the system on this tank as well, but I'm leaning towards an EGR blockage like what is described here:
Sparky's Answers: 1999 Ford F150, P0306 Misfire Cylinder #6
I was about to buy a new coil pack but I'd rather not continue to throw parts at this, as I've read many others do with this same exact situation, only to end up with the same code. I've replaced the coil pack once already a few years ago when I lost a cylinder on the way to work.
I have a 2001 f150 5.4 with 200,900 miles. Just bought the truck about six months ago off my dad when he got a new one. I am now experiencing what seems to be a slight misfire. With the hood up pulling the throttle around 2200 rpm starts making a loud knock. Above that rpm nothing and below that nothing. Standing by the tailpipe it sounds like a small backfire. It Idles really rough and when you get that sound out of the tailpipe it jumps like its hiccuping. And tailpipe is vibrating quite a bit.
Things I have done in the past month include replacing the pcv valve, changing spark plugs, cleaning throttle body, cleaning MAF, took down exhaust to check cats because i was experiencing a power loss and bogging. When the exhaust was off i punched the two rear cats. I ran a bottle of iso heat in the gas. Everything seems to have supported the power problem but now less than a week later i am starting to experience the knock and backfire type sounds.
I have a 1999 F-150 4.2L with a misfire in #5 cylinder. I have replaced plugs, plug wires and coil pack, checked compression (147 psi) and ran 4 cans of seafoam thru it and still getting misfires on acceleration. It'a a 5 speed and it sounds rough and runs a lil rough as I go thru the first 3 gears, then it runs good as I get up to speed and cruises fine at 80mph. I'm thinking a bad fuel injector???
View 7 RepliesMy 97 F150 through a CEL Tuesday night P0301 so I picked up a new plug because it's cheap and simple, but that didn't do anything. Spark plug wires are about 3 months old, I also swapped injectors between 1 and 2, and misfire stayed with cylinder 1. It also gained a tap when the misfire started but only above idle, but it doesn't sound like a rod knock.
I also noticed if you unplug injector 1at idle it taps/knocks 3 or 4 times, however if you unplug any of the others it doesn't do that. I checked and I definitely have good spark from the plug. I plan on picking up a new compression tester tomorrow since mine never was returned. If you take the oil fill cap off it doesn't have any blow by at idle, however if you rev it you get a quick cloud out of it.
I thought about picking up a kit to check the injector pulse.