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.

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

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

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?

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.

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?

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

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