Engine starts to misfire?

when does it show these symptoms? cruising speeds? speeds at certain level and above? fast acceleration?

This guide can help us fix it

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

Please run down this guide and report back.

I have had my ranger to a Ford Dealer and other mechanics and cannot seem to solve the problem that my pickup misses when I drive it. I have changed the mass air flow sensor, spark plugs, and yesterday had a new catalytic converter put in, but it still has the same problem. Someone told me that the distributor cap has a "chip" or "sensor" in it that could be causing this problem. Can you give me more information where this item is located and if it could be an easy and possible fix for this problem? Thanks

Has ECM been checked for codes? check engine light coming on?

Ford dealer should have checked the ECM for code 2 or 3 years ago and "no" the check engine light is not coming on.

Well your vehicle has no distributor it uses coil packs. Thing to do is have shop do a diagnostic scan and drive test if it misses it will be stored in PCM

This truck was running hot so I put a new radiator and thermostat in it.the Check engine light indicated that 2 and 6 was misfiring so I put new plugs and wires and new intake gaskets.the Check engine light went out.Drove it for 1 and 1/2 weeks and the light is back on saying 2 and 6 has misfire.what Could be going on now?Do you think when it was running hot that the head gasket needs to be replaced or could it be the valves?

You also need fuel and compression. A compression test will show if cylinders 2 and 6 are low. For suspected fuel problems, switch the injectors from those two cylinders with two of the other ones, erase the fault codes, then see if they set again for the same cylinders or the two you moved the suspect injectors to.

When discussing an engine-related problem, we need to know which engine you have. If it's a V-6, check if you have six individual ignition coils or a coil pack. With individual coils, switch two of them the same way as the injectors to see if the misfires move to different cylinders. If you have a coil pack and one of the coils fires those two cylinders, chances are that coil is failing intermittently. Ignition coils seem to be a common problem today, more than years ago.

Engine Performance problem
1999 Ford Ranger 6 cyl Two Wheel Drive Automatic

well we have a 1999 ranger witha 4.0 v6 that just wont run smooth, i checked to see what cylinders it was missing on, it infact was missing on the #3,#4and#6 cylinders i rplaced plugs and wires the coil pack is sparking strong this leaves me to believe that it is maybe a timing issue, i have made sure that the firing order is right, i pulled each plug wire off one at a time to find with ones didnt make a diffrence hince the missing cylinders i just cant pipoint what the problem is any help would be great

I would check injector as the coil fires two cylinders each. Meaning that the coil pack it wired as to fire two cylinders so it one and six are hooked together then you have both cylinders dead if there was a coil problem. Here is a pick of the firing order just so you make sure that it isn't wrong. Let me know how it goes.

Recently, while I was out of town, there was a problem with my 1999 Ranger. My teenage son was driving it and it started running rough. Since I wasn't home, my wife dropped it off at a local repair shop. They thought they knew the problem immediately, found a loose or broken connector on the coil pack. Then they said it was the coil pack, then an injector. They went through several items but continued to get a misfire on #6 detected. They finally gave up, only charged for some of the work that they did. Their diagnosis was probably a small crack somewhere in the engine, and would be more expensive to repair than to just replace the engine. Said to just baby it around, it would be reliable for what it is being used for. I was skeptical of diagnosis. When I got home I noticed that after a short trip, it started running hot. I stopped and checked the water, and it was dry in the reservoir. Added antifreeze to the system and monitored. The temperature dropped after a little bit but required turning on the defroster/heater. Started looking at the thermostat and water pump. No obvious signs of failure on the water pump. The thermostat appeared to be stuck so I replaced it, along with a new sensor. Everything seemed to be running fine. Then the check engine light came on. Misfire on #6. I looked at the plug, went ahead and replaced it, just to eliminate it. Drove around several miles, when I checked it had the same misfire. Started doing some swaps between 5 and 6, got the expected response on the code reader. I knew that the #6 cylinder had a new injector, so I checked the wiring. found a nick on a wire going to number six, but was unsure if I caused it or already there. Repaired it so far no misfire. Now all I get is sometimes the exhaust looks like white smoke, other times nothing. Sometimes the truck will run hot, and have to switch heat on to lower the temp. No obvious signs of water in the oil. Any further suggestions?
Randy

WHITE SMOKE: May have a slightly sweet smell if coolant, a burned smell if transmission fluid. Check the coolant level and the transmission fluid level. If the coolant is low and/or the engine has been overheating, pressure test the cooling system to see if it holds pressure. If it does not, the head gasket is probably leaking and needs to be replaced. If only the transmission fluid level is low, add the required type of transmission fluid to bring it back up to the full mark, and inspect the vacuum hose from the transmission for fluid inside. If it is passing fluid, replace the vacuum modulator valve on the transmission.
you said the car runs hot sometime, is this the temperature you feel in the car? or the reading on the temperature gauge?

It is the temperature of the vehicle. We do smell coolant occasionally through the heater/defroster, not always. I will check again, but it appears that the coolant system is holding pressure. Haven't looked at the transmission fluid yet.

I had a message of a misfire on my number 1 cylinder and thought it was old plug wires. I got a tune up replacing wires and plugs and took it home and then eng. light came back on and same message came up. Firestone looked at it for the day and said I have a bent valve. I have been driving it for a month now after that and the engine light will come on and off and the truck will run smooth then run rough at times. Does this sound like a bent valve? If it was bent would it not be doing it all of the time?

If you have a bent valve, it would run bad all of the time. You would also hear it.

If the #1 cylender is the constant problem, have you checked to make sure the fuel injector is working properly? Also, make sure the crank sensor is clean and tight.

Check those things and let me know what you find. Also, if you have other specific questions, let me know.

Joe

ok, long story short: 3 mos ago, I changed plugs n wires, during the swap, one of the new plugs ceramincs got cracked, so I used one of the old plugs that was still in almost new condition. about a month later, I get random bogging down, no torque, mostly during acceleration, but then started getting worse to where it could happen if on the highway passing someone. so I decided to start small and replace the 1 plug that was from the old batch. bought a new plug, put it in and the truck was acting really bad, like it was running on 5 cyl. so I took the new plug out and made sure it was seated properly, and not damaged. put back in, same thing. removed it again and put old plug back in, no change. but since it was getting really late, I could just detect spark coming from the cap on the plug. thought it was the wire, tried 4 different ones, same thing. this morning, took the plug out and the end had a decent amount of carbon buildup and from the threads to the igniter was really burnt pretty good. (see image) also noticed the ceramic now was cracked, put the new one back in, and the sparking from the plug cap went away, but still runs like on 5 cylinders. completely at a loss.

I need you to check the compression in that cylender. Also, let me know if there is any ticking or knocking in the engine?

no ticking or knocking, I will try and get a compression test in the next day or two.
sorry, forgot to mention this is the 3.0L engine.

Not a problem on the engine size. We just need to determine if the compression is low, is it due to rings or valves.

Ive been told by several other people it could be a clogged cat ? since the truck does have almost 170k and its the original cat (Im guessing as I bought it used) this sounds plausible ?
still waiting on the mechanic to be able to get me in for a compression test.

Yes, the cat can have this affect. However, it will usually affect more than one cylender. It's worth checking.

Let me know.

The check engine light came on so I put my scanner on it and it said that cylinder 2 and 6 was misfire so I replaced those 2 spark plugs and it still read the same so I changed all the plug wires and it is still reading that cylinder 2 and 6 has the misfire and the truck still has a miss so what could be the problem?

ok, so I feel like a complete buffoon....

out of 4 plugs I tried, including a brand new one, only 1 of them came out to be any good.
the new one had a weak post, another had a hairline crack that was unnoticeable until you almost looked at it through a magnifying glass, the last failed one was the one in the pic supplied above.
the only reason I even bothered looking was due to checking to make sure the new one was seated correctly this morning, and that is how I found the post was weak. but my coil is still throwing a weak spark to one of the plugs anyways, so my guess is it was a combination of the two, 1 or the other by itself would allow the truck to run almost normal, but both together was killing it.

Have you checked the compression on those cylinders?You made sure you had a nice blue spark on those two cylinders?

Sorry about the delay in responding to you. I lost a family member and things have been...

Regardless, I'm glad it's fixed. As far as identifying that type of problem, anyone would have missed it. When you get new plugs, you don't expect them to be bad.

Take care and let us know if you have questions in the future.

Joe

yes i have did this and the compression is good on both of them.it only missing while its idle but when i run it on the road it runs fine but when i stop at a red light it misses again

Joe, thank you for the help
I am truly sorry to hear of the loss, I hope your doing well.

sincerely
Michael

We need to look for a vacuum leak

Thanks, Michael. After the loss of my mother a little over a year ago, my father went down hill. He was 85 and remained a stone mason nearly till the end. He was always so strong and healthy. I just can't believe he is gone. I guess time will help.

Thanks again, and let us know if you have questions in the future.

Joe

wow i dont even know where to start on this one-i have already talked to you about the problem i've had with this truck and all the things i've changed but now the check engine has come back on and its telling me cylinder 2 and 6 are misfiring again so do you think it is the injectors because i have changed the plugs and plug wires,coil,and checked the compression which is good and it ran fine for 1 week but now its showing 2 and 6 again

You didn't say which engine you have but I can offer a few suggestions. Since you did the ignition coils or coil pack already and you suspect the injectors, try switching those from cylinders 2 and 6 with two from different cylinders, erase the fault codes, then see if codes set for those other cylinders instead that you moved the suspect injectors to.

If your engine uses an EGR valve, disable it or block the port to see if that solves the misfire. Some engines use a passage to each cylinder and those can become blocked. Those cylinders don't get any exhaust gas so they run fine. It's the cylinder(s) that aren't blocked that get the full volume of that inert gas. That displaces so much fresh air and fuel that they misfire.

Was running fine when I parked in garage. When I started two days later engine idled exteremly rough,extreme shaking, engine near stalling. When accelerator is depressed halfway down engine begins to stall then speeds up then stalls then speeds up. This cycling continues as long as accelerator in depressed. I changed gas filter. I also checked fuel pressure at injector rail and found pressure within specs when engine not running key on. When engine barely running at idle fuel pressure increased but still within specs. What do I need to check next?

Have you checked the air filter to see if anything is in it like a mouse nest or anything? If this checks out ok then if you would unplug the Mass Aif Flow meter and start it and see if idles ok then. Get back to me with what you find.

Had already checked filter etc.
Uplugged mass air flow meter as you instructed.
Started Engine and idled and ran engine. Runs normally at idle and when accelerated. I take it the mass air flow meter needs replaced.

Ok if unpluging the mass air flow sensor makes it run normal or better then yes it needs replaced or maybe just cleaned. You can try cleaning it with mass air flow cleaner first. Let me know how it goes.

I cleaned mass air flow sensor with approved cleaner. "Didn't do the trick." Replaced sensor, problem solved, engine running great. I want to thank you for sharing your time and knowledge it is greatly appreciated!
Thank you!!!

My records show the fuel filter was replaced at 55000 miles when a tuneup was done. When your between misses the engine feels fine. Should the Fuel filter be changed again.

[quote:878ae262bc="JimG2"]Engine problem
1998 Ford Ranger 6 cyl Two Wheel Drive Automatic 82500 miles
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My records show the fuel filter was replaced at 55000 miles when a tuneup was done. When your between misses the engine feels fine. Should the Fuel filter be changed again.[/quote:878ae262bc]



Are you getting check engine light on
if so you should get it scanned for codes
also fuel filter should be replaced as well checking tune up.

Great glad to hear it is running as it should again. If there is anything else you need just ask.

There is no "CHECK ENGINE" warning light. You feel the miss then your fine for 30 seconds then it nisses again.

[quote:726f4c5127="JimG2"]There is no "CHECK ENGINE" warning light. You feel the miss then your fine for 30 seconds then it nisses again.[/quote:726f4c5127]


check the tune up

also have cylinder balance test done