Engine misfire? I've been getting the P0301 code?

So plug, wire, injector, valves, compression, all good. So the engine runs good, the check engine light stays on and it makes a metal sound and vibration. What engine? And the dealer must have monitored the engine with their DRBIII and saw that the engine was ok and the fuel pressure was ok. What they did was what anyone would have, there is only the computer and the noise. I hope a flex plate causes this.
Vigration yes, possible crank sensor problems, maybe. Hope it is ok. You have a great van but stay with a good dealer, the firestone uses cheaper parts and cheaper labor. Then send you to dealer. It'll all be ok. Anything I could help with I'll try.

This guide can help us fix it

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


Joe

After all the repairs, engine still misfires and check engine light comes and goes with no consistency. Dodge dealer sees the misfire on their computer when monitoring it. Only vibration comes from the misfire and no additional noise other than the obvious sound of a misfiring engine. Engine is 3.8 v6. Great vehicle...this is the first major work beyond steering rack replacement years ago.

3.8L misfire in number one cylinder. The latest repair was a flex plate, a PCM, and it was returned to you with this problem(dead miss) still present? Is that where you are at now? Joe I'll check back at 11.

You only put let's see 2000.00 at dealer and another 1000.00 at Firestone. You have a good van with all services and parts your gonna need someday anyway. Don't drive it too much on 7. Later I'll tell you how to proceed. If you ask me. OK Check later, ok Don't worry, it will be fixed and its good all the expensive parts were replaced.

PCM and Flex plate are what dealer wants to do next-haven't done it yet because I don't know if it's the right thing to do next. I am hoping there is something the mechanics have overlooked that won't cost me another grand.

I get it. If they swapped out the Injector(not spark plug) it may be the PCM, but you mentioned plug, not injector. Did you have this dead miss when you were just driving along, or did it occur after any one incident? And why is the plate being looked at? Also who replaced coil pack?
You understand that These two items(coil pack, injector) if swapped leave only the PCM or a very unusual wiring problem. Why don't you find transportation, or have them replace the PCM, and hold on the engine repair to see how it runs, if it still has a miss, from the cylinder, then leave it with them til the engine has 6 cylinders and wait on the flex plate. ok Joe

Firestone was the first to completely replace plug, wires, and injector. Dodge switched out all three to make sure they weren't bad. Dodge also replaced coil. They think flex plate is bad and is causing the misfire. They used a scope camera to do a visual inspection of the flex plate but couldn't see anything and want to pull tranny to see for sure. But...they want to run tests on PCM first which will cost me $300 and for that price, I can get a rebuilt one and switch it out myself which I'm thinking of doing.

Good idea. Where from? Dealer or parts store? That's a damn good idea. Unless you could find one on someone elses caravan.
Good luck. I was talking to a friend about this problem, it is a very unusual problem but we both would try a PCM first. I don't understand, the flex plate but I'm sure it must have something to do with the trigger for number one, did anyone pull yhe plug wire to make sure that it is a no spark AND a no injector? I guess so.
I agree, It controls both. And you will have a spare just in case. Well I hope it gets going for you. I want you on the road again ok. Joe

I ordered the PCM from a salvage yard in Louisiana-gave them the numbers off of my PCM so they can match it up but it was no help. Then I have a different shop look at it and they changes the MAP sensor all fixed ! man that was an expensive run around.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers

2003 Dodge grand caravan. Bought it last week, ran great in test drive. One owner. After I got it home it started mis firing. Shakes the engine really hard. I have replaced or repaired the following which have not worked. Any advice would be greatly apprecitated.
Dropped gas tank, cleaned it out, new filters, check gas pressure.
new plugs, new plug wires
new coil pack
new injectors
new wiring harness on it
map sensor
replace PCM (GOT THIS FROM JUNK YARD)
What else is there to do?

Lets start at the beginning. Can you do a compression test to all cylinders please? If you don't have a gauge the auto parts store will rent you one for free, here is a guide.

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

Please let us know what happens and upload pictures or videos of the problem.

Cheers, Ken

I have a KOER P0302 misfire code. Did not happen until I had plugs and wires replaced (bad move). New coil pack also replaced. Injectors cleaned when plugs and wires replaced. Mechanic can find nothing to cause misfire. Takes about 1 week for Check Engine light to come on after being reset.

Hi golfguy54, Welcome to 2carpros and TY for the donation

Cyl no.2 misfire-check the sparkplug/compression and injector for this cylinder-then report back-try erasing the code again

I have not had a chance to do a compression check but what I did notice that makes no sense is that when A/C is on the misfre/stumble at idle disappears.

I was also going to switch the plug with another one and try another wire on that cylinder to see if it makes any difference.

2003 Dodge caravan. The engine start's to stumble just as you take off,it will back fire ever so often when you hammer it at highway speed. I checked the plugs and wire's, i cant find a vaccum leak.Is there anything else i can check? Thanks for any reply..And the check engine lite is on..

Engine is missing at idle and then missing very bad when trying to give it gas. I put new tank filter new wires new plugs. when going down the road it is missing bad. I am thinking its the timing sensor . I have checked at night under the hood no sparks anywhere. what are you thinking? timing belt or chain is fine. still thinking is that sensor. what are your thoughts?

Timing is not adjustable on that engine. It sounds like multiple misfires. You need to get a scan tool on it and watch the misfire counters for each cylinder. That will narrow it down fast.

can some please tell me what i can do to fix the cylinder 3 misfire

A misfire in a specific cylinder should lead you to check the spark plug, fuel injector and compression start with this. If its a no-go check also below

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel

I recently hit a deer and the van ran after the accident. i have now just put a radiator and new bumper on. but now when i try to start it, it will not stay running unless i press the gas pedal

That's because you disconnected the battery. The Engine Computer has to relearn "minimum throttle" before it will know when to be in control of idle speed.

To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.

Engine Mechanical problem
2002 Dodge Caravan 6 cyl Two Wheel Drive Automatic

Hello there I am having probles with my caravan. All of a sudden one morning i tried to start the car but would not start (cranked fine and had gas) I changed the crank position sensor, and got it to start but the noticed a miss in the engine I the but a reader on it and got codes 300,302,304 which are misfire codes. I checked the plugs and plugs wire (seemed ok). My next thoughts are that it might be the cam position sensor? what is your advice Thanks

Engine misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

Hello I have a 2002 dodge caravan 3.3 with cyl 1 misfire, the issue was a random miss fire and cyl 1,4 misfire but I replaced plugs and wires plugs are replaced with oe and beldan wires from napa, still had a miss so I replaced the coil pack, now its just cyl 1 miss
iv done a spray test by taking intake plenum off and flipping the fuel rail up side down and every injector sprayed and had a good spray pattern. Drove it for a little while and then pulled cyl 1 plug and its carbon fouled. I'm thinking next step is compression iv also made sure there was spark by removing the plug and holding to ground.

I think that is a good idea. Let me know what you find.

Tested compression on cyl 1 120psi. Cyl 2-6 were anywhere from 150-160 psi. Pored a little oil in cyl 1 and compression tested again and compression didn't change in cyl 1. So I'm guessing valves are sticking open or head gasket. (It eats coolant to). I'm gonna either take the heads off in the spring.

You never want more than a 10% variation between cylinders. Based on the coolant issue, my guess is you have a bad head gasket.

Hello,
My check engine light came on about a month ago. I did the self check and the error code came back as
P031: Cylinder 1 Misfire

I ran a few bottles of injector cleaner with no help. I changed the plugs and wires, no help.

I then changed the coil, no help.

I am thinking it could be the injector, but I am not sure how I can test it. Is there a simple way without having to remove it or could it be something else causing this error code?
Thanks for your help!
Greg

check wiring or clean/replace the CMP/CKP

Camshaft Position (CMP) sensor is located on rear of cylinder head, just below valve cover. CMP sensor uses a target magnet attached to rear of camshaft and uses locating dowels for proper positioning.
As target magnet rotates, CMP sensor senses the change in the polarity. The polarity change causes CMP sensor output voltage to switch from high-voltage of 5 volts (at magnet north pole) to a low-voltage of .3 volt (at magnet south pole). CMP sensor delivers input signal to Powertrain Control Module (PCM). PCM uses this input signal along with input signal from Crankshaft Position (CKP) sensor for determining crankshaft position for fuel injection synchronization and cylinder identification.

Camshaft Position Sensor (3.3L & 3.8L)
Camshaft Position (CMP) sensor is located on top of timing chain cover, just below thermostat housing. End of CMP sensor is located directly above camshaft sprocket. A notched ring is mounted on front of camshaft sprocket.
As camshaft rotates, CMP sensor generates pulses due to notch areas on the notched ring. When solid metal area on notched ring passes below CMP sensor, voltage decreases to less than .5 volt. When notch on notched ring aligns with bottom of CMP sensor, voltage increases to 5 volts. Switching of the voltage generates pulses. These pulses provide an input signal to Powertrain Control Module (PCM). PCM uses input signal along with Crankshaft Position (CKP) sensor input signal for determining fuel injection synchronization and cylinder identification.

Crankshaft Position Sensor (2.4L)
Crankshaft Position (CKP) sensor is located on cylinder block, behind generator, near oil filter . Crankshaft contains a crankshaft pulse ring which contains 2 sets of notches ground into the No. 2 counterweight.
As crankshaft rotates, CKP sensor generates pulses due to notch areas on the No. 2 counterweight. When solid area on crankshaft pulse ring aligns with bottom of CKP sensor, voltage decreases to less than .3 volt.
When notch area on crankshaft ring aligns with bottom of CKP sensor, voltage increases to 5 volts. Switching of the voltage generates pulses. These pulses provide an input signal to the Powertrain Control Module (PCM). PCM uses input signal to determine crankshaft position. PCM uses input signal along with other various input signals for controlling fuel injection synchronization and ignition system.

Crankshaft Position Sensor (3.3L & 3.8L)
Crankshaft Position (CKP) sensor is located on top of transaxle housing, above flywheel, near corner of rear exhaust manifold.
Flywheel contains 3 sets of slots areas near starter ring. Each slot area contains 4 slots in each set. As crankshaft rotates, CKP sensor generates pulses due to slot areas on the flywheel.
When solid area on flywheel aligns with bottom of CKP sensor, voltage decreases to less than .3 volt. When slot area on flywheel aligns with bottom of CKP sensor, voltage increases to 5 volts. Switching of the voltage generates pulses. These pulses provide an input signal to the Powertrain Control Module (PCM). PCM uses input signal to determine crankshaft position. PCM uses input signal along with other various input signals for controlling fuel injection synchronization and ignition system.

this vehicle has a slight miss fire only at idle.
driver complain of heavy fuel consumption

I would pull the spark plugs to see if one is fouling out from a rich condition. A bad o2 could cause the fuel system to be driven rich all the time, it should show a fault code.

the van misses in idle after warmed up. Also bucks intermittently when stopping and starting at lights.

Installed new spark plugs, wires, ignition coil, fuel pump, fuel filter. Cleaned IAC and TPS. What's next.

Go to this link for further info:
https://www.2carpros.com/articles/engine-misfires-or-runs-rough

I should have done this a long time ago. Posting resolution so it might benefits others.

It was bad egr valve. After reading about how egr works, an open egr valve scenario started to make sense since I had already eliminated other things as described in the original post.

van misses continuously. It gets worse when a/c is on. I have checked the wires for spark, did the compression test, and can hear injectors clicking using stethoscope.

The only engine code I have is related to large evap leak.


Thanks.

hav eit scanned for codes and check fuel pressure with a gauge then have a pro check coils/plug wires etc.

I should have done this a long time.

I used for a few more days and it got really bad. The engine started shuddering while driving. I would have expected that it to set some sort of trouble code but it never did.

It turned out to be a bad spark plug. I found it the old fashion way by plug wires one by one and observed for idle change. Once I found the cylinder causing the problem, first checked its wire by switching from another cylinder and then spark plug the same way. Replaced the plug and everything was normal.

Hi
My caravan is missfire change all plus wire and still.no engine light comes on any suggestion

I'm not sure I understand. You have a misfire, no check engine light, and you replaced the plugs and wires and nothing has changed? Have you checked to make sure the injector is firing? Are you getting spark to the bad cylender? Have you checked compression in that cylender? Fuel pressure?