Under acceleration my engine misfires?

When was the last time you had a tune up because it sounds like the spark plugs got old. These guide will help us fix it.

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

and

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Please run down these guides and report back.

Let us know what you find. Also, I noticed you didn't say the check engine light was on. Is it? if so lets run the codes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back. We have directions and a video to explain how to check fuel pressure, the regulator. Let us know which direction you want to go. If the check engine light isn't on, you may not have trouble codes stored at this point. Also, after driving it, take a look at the catalytic converter to see if it glowing red hot which would indicate it is plugged.

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

Hello .. thanks for the donation .. much appreciated

PO302 is a misfire on cylinder #2 ... it is possible this is because #2 plug is worn .. but more likely due to the PCM software needing to be updated ..as with all computer software updates are required periodically .. I am including the TSB

FLASH: MIL ILLUMINATION DIAGNOSTIC TROUBLE CODES (DTCS) P0300, P0301, P0302, P0303, P0304, P0305, P0306
TECHNICAL SERVICE BULLETIN
Reference Number(s): 18-018-04, Date of Issue: April 27 2004
GROUP:Vehicle Performance

Related Ref Number(s): 18-018-04
ARTICLE BEGINNING
SUBJECT
NOTE:THE SOFTWARE IS AVAILABLE ON TechCONNECT. FOR MARKETS OUTSIDE OF THE UNITED STATES AND CANADA, THE SOFTWARE AND REPROGRAMMING INSTRUCTIONS WILL BE AVAILABLE ON ITIL/ISIS CD/DVD JUNE, 2004.

Flash: MIL Illumination Diagnostic Trouble Codes (DTCs) P0300, P0301, P0302, P0303, P0304, P0305, P0306
OVERVIEW
This bulletin involves replacing the spark plugs, ignition wires and if necessary, reprogramming the Powertrain Control Module with new software.
MODELS
2004 - 2005 (RG) Chrysler Voyager
2004 - 2005 (RS) Town & Country/Caravan
NOTE:This bulletin applies to vehicles equipped with a 3.3L engine (sales code EGA or EGM) or 3.8L engine (sales code EGH), built on or before April 2, 2004 (MDH 0402XX).

SYMPTOM/CONDITION
The vehicle operator may experience a MIL illumination. Further diagnosis may determine that the MIL was caused by one or more of the following DTC's:
P0300-MULTIPLE CYLINDER MISFIRE
P0301-CYLINDER#1 MISFIRE
P0302-CYLINDER #2 MISFIRE
P0303-CYLINDER #3 MISFIRE
P0304-CYLINDER #4 MISFIRE
P0305-CYLINDER #5 MISFIRE
P0306-CYLINDER #6 MISFIRE
DIAGNOSIS
Using a Scan Tool (DRBIII(R)) with TechCONNECT and the appropriate Diagnostic Procedures, verify all engine systems are functioning as designed. If DTCs are present, other than those listed above, record them on the repair order and repair as necessary before proceeding further with this bulletin.
If the vehicle operator describes or experiences the Symptom/Condition, perform Repair Procedure 1 and if necessary, Repair Procedure 2.
If an "Authorized Modification Label" is present and states that Service Bulletin 18-016-04 has been performed, it is not necessary to perform Repair Procedure 2.
PARTS REQUIRED
PARTS INFORMATION
Qty.Part No.Description
6SPRE14PLP5Spark Plug (04686742AD)
104686710AACable/lgnition (Cylinder #1)
104686734AACable/lgnition (Cylinder #2)
104686737AACable/lgnition (Cylinder #3)
104686738AACable/lgnition (Cylinder #4)
104686740AACable/lgnition (Cylinder #5)
104686741AACable/lgnition (Cylinder#6) AR (1)
AR (1)04275086ABLabel, Authorized Modification
AR (1)05011058AALabel, Authorized Software Update (Markets Outside the United States and Canada)

SPECIAL TOOLS/EQUIPMENT REQUIRED
NPN Battery Charger
CH2002 General Purpose Interface Bus Cable Assembly
CH6000A Scan Tool (DRBIII(R))
CH7000A/7001A J1962 Cable with Red DRBIII(R)
TechCONNECT Workstation
NOTE:An updated J1962 cable has been released. This cable has a red colored connector at the DRBIII(R) connection. Use this cable whenever a flash is being preformed.

REPAIR PROCEDURE 1
Replace spark plugs and ignition cables
Replace the spark plugs and ignition (spark plug) cables. Refer to the service information available in TechCONNECT or the Town & Country and Caravan service manual (publication no. 81-370-04062CD), page 81-10.
If Service Bulletin 18-016-04 has not been performed, proceed to Repair Procedure 2. If Service Bulletin 18-016-04 has been performed, no further action is necessary.
REPAIR PROCEDURE 2
Flash Reprogram PCM
NOTE:Whenever a controller is programmed, the software in the DRBIII(R) must be programmed with the latest revision level available.

NOTE:If this flash process is interrupted/aborted, the flash should be restarted and then follow the directions on the DRBIII(R).

Before beginning the reprogramming procedure, remove any old flash reprogramming files from the DRBIII(R) memory. To clear the memory from the MAIN MENU:
Simultaneously press the "MORE" and "YES" keys.
A screen will appear requesting a "COLD BOOT".
Follow the on screen instructions by selecting the "F4" key.
When the DRBIII(R) reboots to the MAIN MENU, proceed to Step #2
With the ignition switch in the "RUN" position, determine the original part number of the PCM currently in the vehicle. Using the DRBIII(R) select:
"DRBIII(R) Standalone"
"1998 - 2004 Diagnostics"
"All (Except Below)"
"Engine"
"Module Display"
Record the "PCM part #" on the repair order for later reference.
Connect the DRBIII(R) to TechCONNECT. Open TechTOOLS and verify that the "DRBIII(R) Status: Connected" message is in the upper right corner of the TechTOOLS screen.
Enter the "PCM part #" recorded in Step #2 in the "Parts Criteria" area and select "Show Updates". TechTOOLS will populate the appropriate calibration.
Select the calibration.
Select the "DRBIII" radio button which is next to the "Download/Update" button.
Select the "Download/Update" button.
Monitor the "Flash Download/Update Progress" window on the TechCONNECT and follow the instructions on TechCONNECT. When the flash process is complete, proceed to Step #9.
Disconnect the DRBIII(R) from TechCONNECT.
Open the hood, install a battery charger and verify battery state is above 12.5 volts.
Connect the DRBIII(R) to the vehicle.
Download the flash from the DRBIII(R) to the vehicle. Using the DRBIII(R) select:
"Vehicle Flash"
Follow the directions on the DRBIII(R) screen. When the flash process is complete, proceed to Step #13.
NOTE:Due to the PCM programming procedure, a DTC may be set in other modules (TCM, BCM, MIC, SKIM, etc.) within the vehicle, if so equipped. Some DTC's may cause the MIL to illuminate. Check all modules using "Module Scan", record the DTC's, and erase these DTC's prior to returning the vehicle to the customer. Erase any DTC's in the PCM only after all other modules have had their DTC's erased.

NOTE:The following step is required by law.

Type the necessary information on the "Authorized Modification Label" p/n 04275086AB and attach near the VECI label

POLICY
Reimbursable within the provisions of the warranty.

You need to check oil levels under the same condition's each time you check, hot/cold oil will give different level reading's ...

Hope this helps .. let me know

Hi Matt,

We need to start by finding out which cylinder is misfiring by scanning the computer and getting the codes then we can start narrowing in on the issue.

Couple issues with what you stated. First, injectors could still be the issue because if they are hung open overfueling then your misfire will not get any better with speed or decelerating. Also, the flashing check engine light means you are potentially doing damage to the engine or exhaust so you want to limit the amount of driving you are doing with this or you will have a larger problem.

Let me know what codes you have and then we can dig deeper. Thanks

Okay. Great, we need to switch things from cylinder 1 to the opposite bank to see if when we swap something the misfire follows. This is the easiest and cheapest way to prove what component is causing your issue. If you already replaced the plugs, swap the injector and see if the misfire stays on cylinder one.

If it does, then take a compression reading on cylinder 1 and then at least two more just to level set. If it is not the injectors, then I suspect you have a mechanical issue (valve or piston ring).

Let me know what you find and we can go from there.

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

Hello, I'm Danny.

It could actually be a few things related to the ignition system. The first thing you need to do is retrieve the check engine light code that is stored in your vehicle's computer. Auto parts stores like AutoZone can check your codes for free and also have a tool loaner program and can rent you a scanner-code-reader. Here is a tutorial showing how to check diagnostic codes stored in your vehicle:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Once you perform this procedure let us know the code number or information and we can then properly diagnose your cylinder misfire issue. Hope this helps and thanks for using 2CarPros.

Go to this walk thru link:

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

If we could diagnose it over a computer, mechanics and doctors wouldn't be needed. The biggest part of their job is to diagnose the cause of a problem, then they spend a little time fixing it.

You need three things to get power from a cylinder, fuel / air, spark, and compression. Missing any of those creates a misfire that is detected by the Engine Computer. Replacing random parts is the most expensive and least effective way to diagnose this type of problem but to waste no money, switch two injectors to see if the misfire moves to a different cylinder. Chrysler has extremely little trouble with injectors but this test won't cost anything. Next, perform a compression test to look for a leaking valve.

Please include the engine size when asking about engine problems. If you have the 3.3 / 3.8L, a common cause of what you described is defective spark plug wires.