2002 dodge caravan Engine misses, sputters and hesitates

[nxm10]

I have a 2002 dodge caravan sport with the 3.3L v-6 the problem im having is when the engine is running in park or a red light the engine misses, sputters and hesitates it seems to be worse whenever i turn on the a/c or heat and when accelerating it sometimes backfires out of the intake area. I have already tried a tune up with new spark plugs and wires and coil pack cleaned the port in the throttle body and replaced the IAC a bottle of injector cleaner. I've also noticed under heavy acceleration there's alot of black smoke from the exhaust

[RIP]

Bit of an odd problem but a few things come to mind.

Does it do it when you come to a stop at a light or take your foot off the gas to slow down with the A/C off? If so, the Idle Air Control (IAC) valve would be suspect. More likely it's opening in the throttle body is clogged. Just need to clean out the throttle body.

Any signs of a week battery? Both the A/C and the HVAC blower put a good load on the battery/alternator. Might have the battery load tested and measure the alternator output voltage. Should see around 14vdc at idle measured at the battery terminals. Make sure the battery connections are clean and tight.

Are you seeing a service engine soon light? Have you checked for codes? You can either do the key dance or head to an Autozone or the like where they will connect a scanner and read your codes for free.

Was any maintenance done just prior to this problem starting?

[nxm10]

Yes when you come up to a stoplight and take your foot off of the gas pedal if the a/c or heat is OFF you can still feel it a little bit but it's worse when there on. Also when the a/c or heat is ON and you accelerate from a stop sign or stop light the van hesitates a bit. The battery is about 1 week old. I have also had it scanned and there are no codes and no check engine lights. Not sure about the maintenance it's been this way since i bought the van about 1 year ago. I will check out the the Idle Air Control valve and update if that fixes the problem or not.

[RIP]

Originally Posted by nxm10

Yes when you come up to a stoplight and take your foot off of the gas pedal if the a/c or heat is OFF you can still feel it a little bit but it's worse when there on. Also when the a/c or heat is ON and you accelerate from a stop sign or stop light the van hesitates a bit. The battery is about 1 week old. I have also had it scanned and there are no codes and no check engine lights. Not sure about the maintenance it's been this way since i bought the van about 1 year ago. I will check out the the Idle Air Control valve and update if that fixes the problem or not.

IAC makes sense then. When you turn on the A/C the engine computer (PCM) senses the added load and opens activates the IAC valve to increase idle rpm. If the throttle body port is clogged idle rpm won't increase. You're saying it gets worse with A/C on fits. You should also notice rough or low idle rpm in your driveway in park with A/C off. Ilde rpm should be 800 +/- 50 if I remember right. In any case it's not going to hurt anything to clean the TB.

Just disconnect the big air intake duct leading to it and spray the cleaner all around the throat paying attention to the small opening for the valve. They actually make a spray throttle body cleaner. Could use carb cleaner.

[nxm10]

Originally Posted by RIP

IAC makes sense then. When you turn on the A/C the engine computer (PCM) senses the added load and opens activates the IAC valve to increase idle rpm. If the throttle body port is clogged idle rpm won't increase. You're saying it gets worse with A/C on fits. You should also notice rough or low idle rpm in your driveway in park with A/C off. Ilde rpm should be 800 +/- 50 if I remember right. In any case it's not going to hurt anything to clean the TB.

Just disconnect the big air intake duct leading to it and spray the cleaner all around the throat paying attention to the small opening for the valve. They actually make a spray throttle body cleaner. Could use carb cleaner.

Ok just replaced the IAC and no change! I also noticed along with the above problems sometimes when im driving and i accelerate hard to pass someone i can hear a small backfire sound.

[RIP]

Originally Posted by nxm10

Ok just replaced the IAC and no change! I also noticed along with the above problems sometimes when im driving and i accelerate hard to pass someone i can hear a small backfire sound.

Uh boy. You normally clean the port in the throttle body first, then you test it, then change it if it tests bad. Well, anyway you've eliminated a good possibility so what's next?

Just a list of possibilities and nothing to really latch onto:
> I'll assume it backfired out the intake. That can be an indication of a lean fuel condition. Fuel pump, injectors etc. You can connect a fuel pressure gauge to the fuel rail test port and measure the pressure off the pump. Could try a can of injector cleaner or have the injectors flushed. Lack of acceleration can indicate a weak pump.
> Could be a vacuum leak. EGR valve, vacuum line, intake gasket etc.
> Chance of a weak igntion spark. Weak battery, alternator output, loose/corroded connection, weak coil output, worn plugs or wires or both. Have the alternator and battery tested. Best battery test is a load test. You can test alternator output as stated in my first post.

[nxm10]

Originally Posted by RIP

Uh boy. You normally clean the port in the throttle body first, then you test it, then change it if it tests bad. Well, anyway you've eliminated a good possibility so what's next?

Just a list of possibilities and nothing to really latch onto:
> I'll assume it backfired out the intake. That can be an indication of a lean fuel condition. Fuel pump, injectors etc. You can connect a fuel pressure gauge to the fuel rail test port and measure the pressure off the pump. Could try a can of injector cleaner or have the injectors flushed. Lack of acceleration can indicate a weak pump.
> Could be a vacuum leak. EGR valve, vacuum line, intake gasket etc.
> Chance of a weak igntion spark. Weak battery, alternator output, loose/corroded connection, weak coil output, worn plugs or wires or both. Have the alternator and battery tested. Best battery test is a load test. You can test alternator output as stated in my first post.

I cleaned the port in the throttle body first and i got the IAC for free so i threw it on lol. It did backfire out of the intake. Im getting good acceleration so i dont think it's not the fuel pump. I put in a bottle of injector cleaner no change. I did get two trouble codes one for small evap leak and a large evap leak found and fixed two leaks haven't gotten the codes since. Im guessing it's not the EGR valve since i haven't got a code for that one yet. The battery is new and the alternator is testing good. Plugs, Wires, Coil Pack new a few months back. Also it hasn't backfired in about a week or so. I've also noticed under heavy acceleration it somtimes backfires and there's alot of black smoke from the exhaust not sure what that means. Also just found out my van is Egr delete
AHHHHHHH this is driving me crazy lol.

[b1lk1]

Have you tried the simple stuff like a tune up (plugs/wires) and have you checked your EGR valve too? Plenum vacuum leaks are also something that comes to my mind, sounds like the PCM is dumping in extra fuel to make up for extra air?? If possible, find someone with a good scan tool and start checking fuel trim values and O2 sensor readings.

To me, this does sound like a tuneup/vacuum issue though.

[TW72]

Hello, am new to the forums.

I'd love to hear how you made out with the rough idling problem. I'm having the identical problem on my '02 GC 3.3 (170K KM). Exactly as you describe. Fortunate to see a wealth of advice here...

Just bought the van a few weeks ago. Other than the occasional hesitation/rough idle (usually more noticeable when warm), very happy with performance.

Just had oil changed as there wasn't a record of last change. Air filter quite dirty - changed that today and gave the TB a good spray-down with cleaner. Changing plugs tomorrow - from the outside, they appear to be old or possibly original...the wires appear new though.

Checked for codes - nothing but "done". Will share updates. Cheers,

[TW72]

New plugs in today.... Engine now smooooth as silk!

[nxm10]

I was just wondering what alternator output would have to do with the problems im having with this van? The alternator bearings are starting to go its making a griding sound now but is still charging the battery.

[Alphabravo]

Originally Posted by nxm10

I was just wondering what alternator output would have to do with the problems im having with this van? The alternator bearings are starting to go its making a griding sound now but is still charging the battery.

The noise you're hearing may not be the bearings. It could be the decoupler. It's like a clutch on the alternator. Some alternator repair shops can replace them. I wouldn't want you to go out and get a new alternator if you don't need one.

search this forum for alternator decoupler, I'm sure you'll find a thread or two on it.

In regards to your hesitation, I can't think of any more advice than anyone else has already given you.

Good luck. Let us know what happens.

[b1lk1]

I still say you got a vacuum leak somewhere. That will cause the engine to dump extra fuel and a choppy idle.

[nxm10]

SUCCESS FINALLY!!!! I replaced the plugs, Coil Pack, and the alternator today and now it runs like a new van again! Thank you to everyone for the great advice and tips.

[Alphabravo]

Originally Posted by nxm10

SUCCESS FINALLY!!!! I replaced the plugs, Coil Pack, and the alternator today and now it runs like a new van again! Thank you to everyone for the great advice and tips.

Glad you got it taken care of.

In your previous post you said you changed the plugs, wires & coil pack a few months ago. I hope you were able to get your money back.