Ford F-150 - 1997-2003 :: Code PO304 - Cylinder 4 Misfire
Sep 6, 2017
I have a '98 F150 4X2 extended cab with a 4.2l with 233K on it. I have no problem with drivability when I drive 5 miles to work. However, a couple of weeks ago when I had to drive 15 miles to the liquor store to get what I needed (I live in a dry county) I got back into my truck, started it and drove of. It drove like crap like I lost a cylinder. Drove it back home those 15 miles, let it cool off, put my scanner on it and got a PO304 code and I think a PO174 (bank 2 lean) code. Went to the #4 cylinder and found the plug had loosened up.
Tightened it back up, cleared the codes, and went through my normal weekly routine of driving to work with no problem. Made a booze run the next weekend and the same thing happened. Limped back home and found another PO304 code. Found the plug to be tight and in good condition but changed all the plugs since they were cheap copper core and had 20K on them. The wires only have 20K on them, too. Installed platinum plugs, drove all week 5 miles to work and back just fine. Made another 15 mile run yesterday and the same crap happened all over again after I got out of the store and drove home.
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For the past few days I've been trying to track down the problem with my '02 Ford Escort. First thing I did was change the spark plugs which smoothed out the engine some, but I still have the PO304 (misfire #4 cylinder). Next I swapped the plug wires between #3 and #4 and reset the ECU hoping the code would come back PO303 (misfire #3 cylinder), yet it still set a code for cylinder #4 meaning the plug wires were good. I then tested the coil and camshaft position sensor which both tested good.
After this I checked the compression on #4 and it was good at 175 PSI. When I removed the #4 plug to test the compression it was gas soaked so the injector is firing, but apparently not the plug. My Chilton's manual says the center pin (ignition/start/run) on the wiring harness for the coil should have 10 volts with the ignition switch in the off position. I checked this and only had 0.1 volts. Where this wire receives it's voltage from and able to tell me more about what to look for or test? I never expected to have so much problem finding a cylinder misfire.
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So 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.
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My 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.
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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 have a 2001 King Ranch F150, which has a 2004 Lincoln Navigator 5.4 DOHC Intech engine installed. The engine was installed in 2005 and had less that 100 miles on it. The engine now has approximately 95000 miles and I have recently gotten a P0307 fault-miss fire on # 7 cylinder. I have installed a new spark plug, COP, and fuel injector. The fault has returned. What is the cause of my problem?
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My truck was running fine the past few days minus a cylinder misfire and a lean code the misfire was due to a coil pack being out no big deal on that part but yesterday on 7/30/13 my temp gauge turned off my truck wouldn't go below 1k rpms and then the over heating light came on. i drove the one mile home and turned it off an hour later i went back out to my truck to get to work and it refused to start.
I decided to just hold my foot down on the gas and crank it and it eventually started drove it to work with the same symptoms. now today its doing the same thing except now the truck is broke down in the parking lot at my job the engine is flooding cause i can smell it last night i changed the thermostat. I can get so that i can get my truck up in running its a 2002 f150 5.4L 4x4....
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I will add as many details as possible :
2000 f150 4x4 offroad package
5.4L with 131k on it
new Dorman intake manifold
new Global Automotive (Ebay) COPs
New Motorcraft spark plugs
About 1500 miles ago I started throwing a code signifying a cylinder 3 misfire. The truck would bog down real bad and then after 5-6 seconds of no power it would return to normal. I tried replacing the COP (both with new and then with one from another cylinder) and plugs but no resolution. So I talked to the local ford service manager and he said it sounded like intake manifold problems.
Replaced the intake manifold and no more codes were being thrown.
1500 miles later and today the truck started having a hesitation/shudder when I was sitting in a drive-thru. I put the truck in neutral and park and neither solved the issue. With the earlier issue, when I would put in neutral and increased rpm, the issue would resolve.
I pulled out of the drive-thru and the hesitation was consistent no matter what the rpm or speed. The truck feels almost sluggish and lacks power. The hesitation is like 2x/second. When accelerating its almost like the rpms and speed hesitate, jump, hesitate, jump.
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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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1997 Ford Mustang 4.6L EFI engine with 67K miles. The engine is actually now in a Factory Five Roadster. It sat on a stand for 5 years but runs well now with the exception of the code. I keep getting a code P0304 (cylinder 4 misfire) and I've checked the plug - the code seems accurate; it is misfiring.
Things I've tried:
1)swapped plugs,
2)this is a dual coil engine so I've swapped coils,
3)the #4 plug is the longest sparkplug wire so I've gotten high-performance wires,
4)heavily grounded the AL head,
5)put dielectric grease on the plug,
Still, ONLY cylinder 4 gives the misfire.
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I have changed the COP and the injector as well as the spark plug. I am still having a misfire on #7 cylinder....
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1997 Ford Ranger with 190K miles has check engine light on with P302 computer code, meaning misfire on cylinder 2. Engine runs rough at idle only once it warms up, which only takes a minute. It is usually fine while driving, but it's a lot easier to feel a misfire at lower RPMs than at higher ones. Added fuel injector cleaner to gas for a couple tanks, no change. My mechanic has checked spark plugs, fuel injector, o2 sensor, and everything is ok. Dry compression test shows good compression. He thinks it may be a valve sticking, which means a valve job: expensive. Is there anything else that can be done? Why is there no misfire when it is first started?
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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?
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I 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?
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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.
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I have a 2000 F150 4.2L and I have 2 codes PO304 & PO174 so far I have changed my plugs & wires,fuel filter,mass air flow sensor, and coil pack...it is still running rough under a load and a little rough on idle..
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1997 chevy k1500 ... I have a misfire on cylinder 3 that i cannot figure out the cause. The idle is rough, backing out after starting is very rough, it seems to pick up at higher rpms but once the truck upshifrts to the next gear it shakes like a leaf in fall. within the past year the engine was rebuilt all new seals a new fuel pump, new injectors, new everything practically. so far i have done the following:
compression test results:125-130psi
fuel pressure test results: 50psi once primed, 50psi with engine running, no immediate pressure loss after engine is shut off
new spark plug wires
new spark plugs
replaced all four o2 sensors
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I am at about my wits end with this P0301 (Misfire On Cylinder #1) code on my 2003 Ford F150 4.6L. I've replaced the coil pack on that cylinder, all the spark plugs, and replaced the fuel injector on that cylinder. We keep clearing the code and it keeps on coming back.
The weird thing is that it only misfires after the truck has set for a few hours and then it only misfires when I first put it in gear. Once I am out of the driveway and on the road it's fine for most of the day unless I let it sit for several hours and then it might misfire again.
We noticed that the connector to the fuel injector is wobbly and doesn't snap tight to the fuel injector (before and after it was replaced) due to the clips on the side not working well. We zip tied it together this afternoon to make it fit tightly to the fuel injector to see if that works.
What could be causing this? Other than that misfire the engine sounds great and the trucks runs very well.
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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???
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I have a 2000 4.6 2wd f 150 ext cab. I started to have a misfire problem on cylinder 8 every so often usually in the mornings or if there was moisture in the air. It gradually got worse over time and when I got it read it had gone to cylinders 5,7, and 8 with the misfire codes which said misfire cylinder whichever primary/secondary circuit misfire and it has now gone to cylinder 2 as well. I replaced all the coils and the plugs with autolite platinum plugs and new coils for this motor and the problem has not changed. It came right back after I cleared the codes, what possible causes I could check out....
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I have a 2001 King Ranch F150, which has a 2004 Lincoln Navigator 5.4 DOHC Intech engine installed. The engine was installed in 2005 and had less that 100 miles on it. The engine now has approximately 95000 miles and I have recently got the P0307 fault-miss fire on # 7 cylinder. I have installed a new spark plug, COP, and fuel injector. The fault has returned. Any clues to the cause of my problem?
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