misfiring engine?

Just for kicks, use some seafoam. About 8 bucks from your local parts store. If it makes a difference after adding it in your gas tank, you know you've got buildup in your injectors. Also might be a distributor.

This guide can help fix it

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

Please run down this guide and report back.

I just bought this car a day ago for cheap, but soon found out it jerks bad when I start accelerating from a red light. I am thinking transmission shift solenoid. I checked the transmission fluid for quality and level no burnt smell good color and good level. possibly engine mounts? but they do not look too bad. And no check engine light.

try cleaning throttle plate on both sides and IAC hole with choke cleaner and check fuel pressure with a gauge auto parts rent it. Also, check for a vacuum leak like a line off etc. if engine runs bad so will transmission a shift solenoid would affect it when it shifts. See link.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

It is shifting rough especially when it goes into third gear not so rough if i keep the rpm down.

have a transmission professional scan for codes. it may be a valve sticking or a clutch pak worn out.

2001 Neon 2.0, 137K, auto trans

A little background:

Car was running fine, no issues, no engine lights or codes. I did some preventive maintenance including timing belt, water pump (Oh what fun THAT was!), crank position sensor, cam position sensor, coolant temp sensor, and spark plugs. Car ran fine afterwards for a couple weeks around town and then week 3 when on the highway for about an hour the MIL light came on. Code was 0300 - random misfires. Car didn’t actually seem to misfire as it didn’t*****, sputter, kick, backfire, or anything else you’d expect with an obvious misfire. Went ahead and then replaced the plug wires and ignition coil and checked the already new plugs for anything obvious…all seemed well. Reset the code and car ran fine with no codes for a few days around town again and then when on the highway again for about another hour, MIL light came back on. Codes read 0300 and 0302,0303 for cylinder misfires. Again, no obvious signs of an actual misfire as car never acted up or ran funny. It has always ran fine before and during this issue.

Question is this:

Does the vehicle need to have a cam/crank relearn procedure initialized or does the PCM just adjust itself as time goes on? Or, is there something else I may have done or didn’t do that could be causing the random misfire codes? I’ve heard it both ways that yes it needs a relearn and no, it doesn’t because this PCM doesn’t even allow for it as it just adjusts itself anyway. I’d like some real advice from someone in the know before I go out and buy a new scan tool that has the relearn capability. I’m a handy guy but all I’ve got now is just a reader, and I don’t mind getting a new one with more capabilities, but just really need some good advice first.

Thanks,

Brian

When the timing belt is replaced, the cam / crank relearn procedure needs to be done on this vehicle. Connect the scan tool to the data link connector under the lower left side of the inst panel. Turn the key to the run position (engine off) and select cam/crank relearn procedure by accessing engine diagnostics. Select miscellaneous then crank/cam relearn and follow the scan tool screen.

If you haven't done this (you said you didn't) I feel confident that is where the problem is coming from.

Let me know if it works or if you have other questions.

Joe

Ok, I'll pick up a new scan tool with that capability and do the relearn. I guess I forgot to ask, is it normal that it would pop up a misfire code if the relearn isn't done after the timing belt or should it have shown a different code such as a timing issue?

It is normal. What is happening is the cam / crank sensors are not working in sync. At low RPM's the chances of a misfire are slim. However, when you take it out for a long period of time (higher speeds) it can set the code. The reason you didn't feel the misfire is because, in reality, it wasn't a true misfire. It is a timing issue the computer thinks is a misfire.

Before you purchase the scanner, contact your local dealer with the VIN and ask if there are any updates that need programed into the computer. Off the top of my head, I can't think of any for a 2001, but I would hate to see you spend the money on a scanner only to find out you have to take it to a dealer for an update. The scanners are not cheap.

Let me know if you have other questions.

Joe

Thanks a bunch Joe. Right now my daughter has the car 2 hours away at school so it may be a few weeks before I can get it done. I'll let you know.

I really appreciate the concise and detailed explanation and responses. It really helps the determined do-it-yourselfers like me. By the way, I've got another issue with another vehicle I'd like your advice on but I want to make sure you get the donation/request. Is there a way to make sure you get it?

The engine misses like when you need a new coil. That's been done but it didn't help. The spark plugs and wires are also new.

I'm glad to help. As far as a do it yourselfer, it sounds to me like you know a heck of a lot more than that. You basically rebuilt the vehicle.

Take care and let me know if you have other questions.

Joe

You also need fuel and compression. Have you checked for spark at all four cylinders? Do you have the single or dual cam engine? Have you checked the diagnostic fault codes to see if there's a misfire code indicating which cylinder is responsible?

One last thing, I just reconfirmed what I told you. I checked the manual. When replacing the timing belt, the last step is exactly what I told you. Now I feel even better with my answer.

Take care of yourself and let me know how things go.

My car acts likes its missing when u start up hill. Doesn't make any noises just kinda acts like its chugging a bit. What could it b? How expensive to fix?

Many things can cause this type of a problem. Has the check engine light come on? Have you checked fuel pump pressure to make sure it is within the manufacturer's specs?

Engine Mechanical problem
2000 Dodge Neon 4 cyl Front Wheel Drive Automatic 362000 km

i have a 2000 neon with a 2 liter, it has a skip in the motor.it is a pretty bad miss i can barely take off. i hold the pedal then after a few seconds(5-10) it finally takes off but with no power a bad skip and the occasional backfire. sounds like little pops in the exhaust. it has troubles climbing hills and even picking up speed on straight aways. it seems better at high rpm(3000). then it shifts at a little over (4000)rpm and no power again.

i have tested the fuel pump from the fuel rail. it had 55 pounds pressure, and doesnt lose any as it idles or revs up.

i have tested the compression. cylinder #1(180) #2(180) #3(150) #4(190-200),i tested them all at least 2 times each.

i have changed the spark plugs.it does not seem to take much if any oil or prestone. and the spark-plugs all look the same at the firing end. with the engine running idle,i pulled off the spark-plug wires one at a time, they all had the same reaction.

i changed a sensor in the intake. (sorry i dont know what it is called). it seemed to of helped for a few minutes but shortly it was back to its old ways(skipping).

i have also checked most of the vacuum lines they seem to be ok.

i am getting pretty lost with this problem. if anyone has a opinion i would really appreciate hearing it. thank you

Oxygen sensor
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Cylinder 4 misfire, replaced spark plugs and cables, happened again. checked compression on cylinders as follows: 1-60psi, 2-60psi, 3-50psi, 4-70psi. I believe this point to a head gasket, but unsure. Any assistance or guidance is greatly appreciated.

Steve

Check injector no.4

ok, thanks. Car actually has 210,000 miles on it. Not 210.

When I performed the compression test I had removed all spark plugs after engine was warm. Should I have only removed one at a time as I was testing each cylinder and replaced before moving to next cylinder?

Number 2 cyl spark plug wire poped off and caused engine to run rough and misfire. put wire back on. later (2-3 wks) same thing happened again. This time check and changed plugs. I noticed that #2 Plug was very loose and had significant carbon/exhaust soot looking material on the outside of the plug. Changed all 4 plugs. I still have misfire problems at low/ pull away from trafic light speeds. The problem has significantly decreased since changing plugs but is still there. (does not do it at highway speeds unless under load - going up steep hill) When reading the codes through the odometer it just says #2 cyl. misfire. could this be an injector problem or is it a burnt valve?
Thanks

I would replace the wires first. They dont like having the hot exhaust on them.If the misfire continues, we will have to look a little deeper. For now , do the basics. what kind of plugs did you use?

a female friend of mind told me she wanted me to change her spark plugs, she said she got a diagnostic and they told her she had a misfire on cylinder number one what could be the reason for that

bad plug, bad wire, defective coil, vacuum leak, bad injector or low compression.

she needs a real diag from a shop that can pinpoint the exact failure. guessing is expensive and in most cases wrong.

Roy

My wife bought a 2000 Dodge neon from a used car lot about a month ago.The car ran fine until yesterday.She checked the oil and it was low so she added some.When she did the check engine light came on.The car now lopes and acts as if its going to stall.She had dianostic ran it came back (plug no.2 misfiring).She took it to a shop and they checked and said that was not the problem.What do you think the problem is?

what did the other shop say it was and do you have the exact code ?? would help

thanks
jim