02 Dodge intermitant Misfire Driving Me Crazy

I have an 02 Dodge Caravan 3.3 L Flex . It had initially stalled and wouldn't start. Check engine light was on. Had it towed to a Cert Mech. He said it needed a "Major" tune-up. I let him do this. It included: New Coilpak, plugs, plug wires, cam-sensor, crank sensor. That's what was on 1st invoice. It started, but was still running very rough. He then recommend a new PCM. After choking on his estimate, and paying the initial invoice, I decided to let someone else have at it. Mech # 2 installed a "Rebuilt" PCM, New Battery, and a PCV Valve. It runs good now BUT, ...It has this weird idle Misfire. The only time it happens is at a stop light when at idle. And it doesnt do it all the time. This check engine light is not on...I really need some help! At this point, all I want to do is sell it.I have over 1K in repair costs and still can't get rid of this misfire. Please Help.

Doing regular maintenance can weed out problems before it happens.
Try cleaning the Massive Air Flow (MAF) sensor,Incoming Air Control (IAC), and throttle body.
Cleaning and test's are so much cheaper.

New ignition parts, because of Age + mileage is good, but let's not throw darts @ it!
$1k for a bad tuneup is shameful, see www.rockauto.com

Thanks Daniel for the quick responce. Will go to Autozone for the cleaner & instructions.

Do a Google ''Youtube DIY Auto scotty channel''
Use only CRC MAF sensor or electronic cleaner on MAF sensor, and throttle body cleaner on throttle body.

Caution - Don't use carb cleaner, it's to harsh on rubber seals, gaskets, and clear coat.

Again, thanks. The $1000. was from 2 different Mech. I wish I was mechanical. I'm learning quickly though, even at 63 yrs old!

63years old + new to Automotive forums (AF), that's great!
Learn to Google '' <make> <model> <DTC> ''

DTC - Diagnostic Trouble Code can be pulled from any local Auto Parts store for free.

You can find Do It Yourself (DIY) tutorial videos on youtube.
Learn to Google ''Youtube Auto DIY video''

First of all this engine does not have a MAF. It's a speed density system. Was it misfiring before it died? Just because parts are new does not mean they are good. Hopefully Bosch spark plugs were not installed.

Thanks for your input JP. I havnt looked for the MAF yet. To answer the question, yes it was on a freeway and started running really bad. I pulled over, and tried to "feather" it but it eventually died. The check engine light was on at that time. I tried to restart then, but it was running extremely rough. Not wanting to do any damage, I had it towed. Thats when all the replacing and tuning up started. Plugs are NGK...

The Massive Air Flow (MAF) sensor, MAP (Manifold Pressure) sensor, and Air Mass Meter sensors are all used for an air metering device.

YES - My bad, Dodge uses a MAP sensor, it can be bought for $30-$50 range.

I really don't care who's name, or rubber stamp is on it, $1k parts + service + 2 mechanics = rape!


Air filter -> Air metering system -> Combustion Engine - > HO2 sensors are used for a feed back signal, so the ECU/PCU can formulate the Air/fuel mix

Doe's the idle change, if the the HVAC on max cool or off?

Daniel The engine idle seems to be at 800-900 and doesn't change notably when the AC is turned on to MAX. Thanks. Also there doesnt seem to be a MAF sensor, but there is an electrical something in the rubber ducting.....I'm still going to clean the throttle body & assy today and ask about the MAF...Thanks for your help. This seems to be a needle in the proverbial haystack. Does the MAP attach to the aluminum intake housing? Is that where I should be looking to clean? The throttle cable assembly is hooked on the opposite side.

The Massive Air Flow (MAF) sensor, MAP (Manifold Pressure) sensor, and Air Mass Meter sensors are all used for an air metering device.

** YES - My bad, Dodge uses a MAP sensor, it's somewhere on the intake manifold.



The sensor on the air duct work is probably a Incoming Air Temp (IAT) sensor, yes it should be cleaned.

If the IAT sensor is dirty or bad, it would cause a cold hard start.

I cleaned the Throttle Body Assemble..actually scrubbed with a toothbrush and re-assembled. All parts , including the idle control sensor, look new and put back together. Intake Air Temp sensor cleaned. Put in a bottle of CRC injection cleaner, filled the tank, and took this bitch for a drive. It drove wonderful on the freeway, about 30 miles. Turned it around and headed back thinking maybe......As soon as I stopped at a light, there it was...AGAIN! THE SLIGHT MISFIRE! BITCH IS BACK! I have been advised that there might be a injector wiring harness issue. Or maybe a injector issue. Either way, I'm going to try and rebuild the harness, as it is the easiest for me at this point and a new harness kit is only $45 at the dodge dealer. How do I check the seperate injectors?????:confused: STILL NO LIGHT OR CODE!!!!!!IT STARTS UP PERFECTLY!!!! NO LAG....

How many miles are on this car?
Are both cold/hot starts good?
Let's monitor, and look for more symptoms.

You can do a DIY out of car injector service, by taking injectors to any local diesel shop for a micro bath, new injector seal, and the flow rate tested on each injector.

Daniel ....Thanks Again for the responce. This van has 139000 on it but has been taken care of. We bought it new. Timely service. Oil change and lubed every other month, even though my wife and I drive it less than 600 miles a month. No major componants changed in the last 3 years. Even then, it was an AC compessor, not anything to do with the engine. Yes both cold and hot starts are a one click start. Do I need to take all the injectors out.? To have these tested? "I do have the time but not the tools ".......Thanks again. Gordon

I wouldn't put monies on injectors yet.

Because of the Age + mileage, it's probably time for a new IAT sensor + up stream H20 sensors.
Both sensors are used by the ECU/PCU, to formulate and maintain the air/fuel mix.

Professional tune up -
1) New Air & fuel filters
2) New MAF/IAT sensors
3) Clean throttle body, EGR & IAC
4) New plugs, and wires.
5) New upstream H2O sensors.

If the miss is consistent enough, a power balance test may point you in the right direction. This involves disabling one cylinder at a time, and seeing which one causes the LEAST rpm drop. Disabling can be done by either disconnecting spark plug wire or injector, whichever is easier. If not I would suspect EGR trouble (valve not seating), which the engine at cruise can handle, but not at idle.

Daniel and everyone that helped me with this.THANK YOU... I sold it! Had it listed on Craigs list for $4000. The new owner is a mechanic. He was aware of the problem and said his other van, (one like mine) had the same problem and it was a wiring harness issue for the injectors. Didn't seem to be to concerned....anyway thanks again!

Was this a intermittent misfire on the same cylinder?

I once found an extra fuel injector seal in the fuel rail causing the same type of symptom.

Congratulations,
Divorce is one way of resolving three of your problems!
(1 van + 2 mechanics) = 3 strikes

See Google ''dodge caravan fuel injector wiring problem''

** Copper wire breaks, just like old school copper spark plug wires.
Constant bending, movement (rpms), heat, and time = broken copper wire