06 Dodge Caravan 3.8 very poor acceleration & mpg

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I recently purchased this Caravan from a shop and found out it had issues shortly after I got it home. First off the engine light was on, but not on if you know what I mean. I found this out the first time I drove it after I brought it home after I got on the freeway and it wouldn't even make it up to 40 mph. I found out it had a P0404 dtc, so I replaced the EGR. Now there aren't any codes, but there is still very poor acceleration and currently the mpg in the data center lists it currently at about 14.1 mpg. It seems to be shifting ok, just seems to really be running rich. Unfortunately I don't know a lot about this vehicle as I just got it. It has high miles but supposedly the engine was redone 10k miles ago. The valve covers and wires look new, and engine looks pretty clean but must still be the original block. Has anyone else had a similar problem with their Caravan? Any suggestions on what to check first since there aren't any dtc's? I'm leaning towards a possible bad TPS but would really like additional input as it's cold outside, I don't have a garage to work in, and for the most part basic hand tools/equipment. Any suggestions or input would be greatly appreciated.
 
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<span style="font-family: 'Verdana'">I'd do an exhaust back pressure test is the first thing I'd do. Then if it passes the back pressure test, I'd be looking at the MAP sensor circuit.</span>
 
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Suspect possible bad cat. Edit: Test with vacuum gauge, you might get some idea as to whats going on.
 
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Agree with Trav 100%, check the cat(s). Also check the O2's and MAP sensor. It might require a trip to the Dodge dealer or a good local garage for the correct diagnosis. They will have diagnostic tools not typically available to the home mechanic. Check the condition of the muffler too.
 
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Yup, blocked cats could cause that, and the O2 sensor cause.the rich condition. Surprised you didn't test drive on the highway. How many miles?
 
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Originally Posted By: Chasingdreams3n8
I recently purchased this Caravan from a shop and found out it had issues shortly after I got it home. First off the engine light was on, but not on if you know what I mean. I found this out the first time I drove it after I brought it home after I got on the freeway and it wouldn't even make it up to 40 mph. I found out it had a P0404 dtc, so I replaced the EGR. Now there aren't any codes, but there is still very poor acceleration and currently the mpg in the data center lists it currently at about 14.1 mpg. It seems to be shifting ok, just seems to really be running rich. Unfortunately I don't know a lot about this vehicle as I just got it. It has high miles but supposedly the engine was redone 10k miles ago. The valve covers and wires look new, and engine looks pretty clean but must still be the original block. Has anyone else had a similar problem with their Caravan? Any suggestions on what to check first since there aren't any dtc's? I'm leaning towards a possible bad TPS but would really like additional input as it's cold outside, I don't have a garage to work in, and for the most part basic hand tools/equipment. Any suggestions or input would be greatly appreciated.
If you feel it is running rich and have no DTC's I will check fuel pressure first, if it is that then a fuel pump replacement is in order, since the fuel pressure regulator is part of the fuel pump assembly; although plugged cat's (there is one cat only in these vans) are a possibility I've never heard of one in these vans, as a last resort I would crawl under and check that the exhaust is not crushed somewhere. Go here http://forum.chryslerminivan.net/forum.php and you most likely will find your answer, use Google instead of the site search feature it is better.
 
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Originally Posted By: ron17571
O2 sensor first came to mind. Easy things first.
Yes, but it usually sends a code, also it will not prevent the engine to make enough power to reach above 40 MPH. Despite of been detuned in 2006 that V6 does 205 HP.
 
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Originally Posted By: Trav
Suspect possible bad cat. Edit: Test with vacuum gauge, you might get some idea as to whats going on.
This. With a plugged cat or exhaust the vacuum will be normal momentarily and then gradually drop as the back pressure builds.
 
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It's pig rich. The EGR was probably plugged with soot because of the rich condition. The O2 sensor is toast. Check the plugs. The porcelain should be white to very light tan. Any vacuum leak will cause this problem. Or a leaking HG. Your plugs can tell you a lot. It could be the cat, the engine was rebuilt? Why? Either the 3.8 ring issue or a blown HG. If it was overheated, then probably a HG. You will need a step by step trouble shooting. Plugs first, then vacuum test under load. Depending on what you find, then replace the O2. Good luck, Wayne
 

Chasingdreams3n8

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Sorry for the late response... As it accelerates to 40mph it's at about 3k, but after it shifts it drops down to the 1.5-2k range. It almost feels as if it's pouring in fuel until it gets up to speed and then shifts. I didn't get to drive it on the highway as there wasn't exactly one near by. It being one of the colder days in Wisconsin so far I didn't think too much of the slight sluggishness at the slower speeds as it seemed to shift just fine and there was no visible light on. The muffler and exhaust seem to be ok. No noticeable damage and it's quiet yet. Surprisingly it doesn't have the what seems to be standard dodge rumble.
 

Chasingdreams3n8

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I can't say that it was a reputable shop... If it was then the engine light would have been on. I haven't taken the instrument cluster out, but I'm guessing either the bulb was pulled or removed. They had to have known that they gave it to me with the dtc there.
 
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Does the CEL come during the bulb test- when you turn the ignition to on, all the various dash lights should come on for a couple of seconds.
 
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generally I find these pretty easy to work on. keep checking to see if more codes get pulled. does it run rough? is it getting up to temp? does it idle rough? have you pulled the air cleaner? visually inspect the throttle body, check tension in throttle cable? does it rev quickly in neutral? the 3.8 in ours is a screamer and will lay two streaks of rubber. it has immediate throttle response and has gobs of low end torque. it uses 1 qt of oil per year (~3,000 miles per year). for kicks and grins check condition of ATF. what does the heat gauge register? is coolant level ok, and the hoses firm (and hot) at operating temp.
 
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sorry it doesn't sound like helping (at all) but personally, I would not buy used vehicles from shops (presumably bodyshops or mech repair shops), for if there's profit to make from cars that can be easily repaired, they would do so in a heartbeat (instead of selling them to you). Sounds like you'll have to toss a whole lot hard-earned mullah in order to get this baby going. See if there's any means of offloading and get something better? Q.
 

Chasingdreams3n8

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The CEL does not turn on during initial start up. I realized this as soon as I got off the freeway and luckily transferred all my tools into the van before I left, which included my generic code reader. It immediately came up with a dtc, so I know there is an issue with it being pulled or whatnot. It doesn't seem to run rough, the engine especially at idle is very smooth. No unusual noises, and in fact the bearings all seemed pretty quiet when I listened to them. The air cleaner looks fairly clean, the oil and ATF look pretty clean, but didn't check coolant. It seems to run at a normal operating temp.
 
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<span style="font-family: 'Verdana'">Go to Harbor Freight and get an exhaust back-pressure gauge and an oxygen sensor socket. Anything over 2 PSI at any RPM is a clogged catalytic converter.</span>
 
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