engine is misfiring?

It sounds like you may have low compression in one or more cylinders here are two guides to help us fix the problem.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/how-to-test-engine-compression

Please run down these guides and report back.

Engine Mechanical problem
2002 Ford Ranger 6 cyl Four Wheel Drive Automatic

i have a 02 ford ranger and its not running right and i dont know whats wrong with it i went mudding in it and now i read the codes an it sead system to rich bank 1 and 2 then something wrong with the maf but this is what it dus i pres on the gas it suck air and bogs down then the rpms go back up and the truck gos if you could just tell me what is wrong

Hello,

Well first thing you need to do is clean out all the mud. Check all connections under the vehicle, making sure they are clean of mud and that no mud and or water got into the connections.

Also pull the MAF out of air duct and check for water and mud.

Check for broken emmission tubes, vacumm leaks...

Post findings....


.

Ok, so I have had a misfire with cylinder 6 two separate times in 2 years. Both times I replaced all the spark plugs and wires (regular tune up). The code goes away for a while but the truck idles horribly, especially when I come to a red light. I change the oil regularly. I have changed the fuel filter, no change. I have changed the air filter, still rough idle. I cleaned the idle air control valve, and the MAF, and the throttle body. It still idles very rough but was not throwing codes for 2 months just rough idle. Now the check engine light sometimes comes on when I have driven the truck for a while and the engine is very warm, and it ONLY comes on when I am idling at a stop. It blinks until I take off again and then it goes away. I changed the cylinder 6 plug and I still have the problem! I have no idea what to do now!

Check the compression and injector for no. 6 cyl.

I had a compression test done #1=115, #2=100, #3=110, #4=100, #5= 105, #6=110, I was told that was good. Im still stuck.

Engine running rough or misfiring can be cause by the following:

1.Defective spark plug.
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.

Spark plugs and wires are new and good.
Compression check is good.
I only get the check engine light once in a while and only at idle when the engine is really hot. However the engine has a rough idle problem hot and cold, all the time, sometimes the idle is so bad, the truck feels like its about to die.

have 03 ranger 3.0 that is misfiring. replaced coil and heads, had valve job done, checked compression all good still misfirers! what else could be wrong? thanks

Is a code set?

Double check the IACV, EGR valve and TPS

What does that mean?

Ok, so I have not been able to double check those parts yet. HOWEVER I disconnected my MAF sensor, cranked the truck and she purred like a kitten, I have never seen an idle that smooth in this truck, when I hooked the MAF back up, rough idle again. I took the Maf off and cleaned it again. Still very rough idle. Any more thoughts? Do I need to get a new maf?

Check engine light on?

Check and test the wiring back to the computer for short or open if okay consider a new one

Yes and its flashing

Ok, so my buddy has the same truck as me but a year newer. His runs fine. I switched our maf sensors and no change. I guess it's not my maf. The idle is HORRIBLY rough, the engine is shaking severely. I pulled each plug wire off of the plugs to see if there was any change in idle. I noticed that there was no change when i pulled the wire for #6 (this is the one that sometimes throws a code) I also noticed that the idle does not change much at all when I pulled the wires of of the #4 plug and the #5 plug (of course not at the same time). So there is a pattern here, those plugs are on the same side of the engine. So I went and swapped out my new wires for some more new wires. No change. Currently horrible idle and no codes.

Go to an Auto Zone have codes pulled then post

Check the engine compression both wet and dry tests

Codes p0301, p0303 and p0305 which is a misfire in cylinders 1,3 and 5, and they said something bout the emissions.

compression tests were done a couple of days ago, checked out good

I have a 2002 ford ranger with over 107,000 miles on it. Not too long ago i got a batch of bad gas and my truck starting misfiring when i would crank it up and then even out slightly when it got to operating temp, so i changed the fuel filter. Got slightly better, but then my cel came on and i got it scanned at oreillys, and it said i have a cylinder misfire in #3...i didnt have the money to change the spark plugs, so i drove around for about 2 weeks with it misfiring, until i recently changed all 6 spark plugs with iridiums instead of platinums, and that seemed to help but then i heard this squealing noise coming from my engine, so i checked it out and it was my idler pulley and belt tensioner pulley so i changed them both and it stopped. Well then i heard squealing coming from the back of my engine, and everything i read told me it was my cam shaft synchronizer, so i changed that out last night. As soon as i changed it, and started it up, the cel went off, but that misfire is still there...I would really like some suggestions because im about to rip my hair out. could it be the coil pack needs to be replaced? I have been letting my truck sit for two weeks while ive been working on it, so could it just be bad gas?

Was the same engine miss there before heads r&r? Has fuel injectors been checked on those cylinders? is miss at idle and under acceleration? Have vaccum leaks been checked ?

Run an injection cleaner thru it and see what happens, also is the check engine light coming on or has flashed? If so try scanning for code/s.

check your fuel pressure should be 60-65 psi engine running.

It was not missing before. Could it be something electrical?

i have put some gum out in the gas for the injectors, we will see what that does. I only get a code every one in a while, when i come to a stop after the engine has been running for a while, the light will blink, when i take off, the light usually goes off. A couple of times it stayed on and i got it checked and it always says cylinder 6 misfire.

and how do i do that? and if it isnt running 60-65psi what is causing it?

The cylindes that are effected indicate an intake leak. Check injector connections if good . Consider pulling top intake and give close look at gasket seal.

Pull the valve cover and see if a rocker arm is loose or if a valve is getting stuck. If that checks out, go ahead and do a cylinder leakdown test.

you need a fuel pressure gauge hooked to the fuel rail. you check it by turning the key to ON

Ok, just an update on my cylinder 6 misfire. Remember, it only misfires when the weather is warmer and the engine has been running for a while. The misfire is ONLY at idle. I have been through 3 sets of wires and plugs now. I have changed the coil pack. I have changed the fuel filter, oil, and pcv valve. I have cleaned the MAF sensor and the IACV. My truck is not equipped with an EGR. I have swapped the injectors around. I am still getting the misfire in cylinder 6. I also had a compression test done and it was ok. I am LOST.

Mine is a 2000 Ranger with 93000 miles. The idle is rough and the check engine light comes on for a couple days then the light goes out and it seems to run fine for a while. Then it comes back again.

At the last smog test last month it showed a cylinder 6 misfire and a evap control valve problem. We changed the evap valve and re-did the test; passing this time. The mechanic said it probably needed a valve job to fix the problem...$$$$. The idle is not as bad as you describe yours, but I'd like to solve it sooner than later and if it can be done without opening up the engine, that'd be great. Oh, the mechanic did a compression test and found #6 was at about 70.

how to find the reason my 3.0 ranger detechs a misfire in cyl 3 i have already changrd my plugs and wires, coil pacl, pcv, coil pack and catalytic converters what shoul i check next and how

thanks for the info, I already had a compression test done and it checked out great in all valves. i am still clueless lol!

Is there spark at #3 plug? Injector working? Has compression been checked?

yeah i just got it back , replaced the fuel injectors and had a comp test it was good but said something about loosing compression and something else may be cracked like a vowl or somthing the tech qwas asian and very hard to talk to and understand. but it has spark and compression and the light has not come back on yet but he said it was off and on do you have any idea on what he is talking aboutwith the voel or vaul something like a flap that opens and closes

I too am having this problem but mine started out like yours doing it every now and then but now it's all the time. I have changed the follow
1. Plugs and wires
2.coil pack
3.checked vacuum lines
Mine is misfire in cylinder 4 the weird thing is every once in a great while you will start it and it will purrr like a kitten for about 30 to 45 sec then starts running horrible again. It's litterly driving me crazy its my only car at the moment so been having to drive it like that. I've done the test where you put gas to the floor to disable injectors to see if it sounds like it's got a dead cylinder but sounded normal. If any body can help it would be greatly appreciated. Next thing in gonna do is try to test the injector in cyl 4. But just a note before it started this it ran perfect no ticks or knocks motor was very quiet. But if any body has any suggestions please let me know thank you. It's a 2001 ford ranger edge 4.0 motor.

Think he was reffering to a vaqlve possible seat problem that will ocassionaly not seat properly and cause miss. Try a product called SeaFoam to clean out combustion chamber and valves.

Injector go out in these cars. I would test the injector like you have suggested. here is a guide to help test the injector:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Please run down this guide and report back.