I have a 2006 Dodge Grand Caravan (3.3L regular fuel) with almost 90k miles on it. I change the oil regularly every 3,000 miles, and just upgraded the rear shocks to heavy duty Monroe Sensa-Track Load Adjusting Shocks (#58620). I also have winter Bridgestone Blizzak snow tires on all four wheels. Air filter is a K&N, oil filter is Bosch.

Up until recently this has been a good, reliable car for my wife; however, after driving it across the country towing a fairly heavy trailer, I've noticed that the van is now sluggish and performs poorly, even unloaded. Coming across the country, I was forced to buy gas that had a heavily ethanol mix running through the Plains states, and am beginning to wonder if that might not have done something bad to the fuel system. It is running at about 2100-2200 RPM at 55mph, but to accelerate it from there it has to kick down out of overdrive, which it has never had to do before. Generally it is just feeling like it is lacking oomph and feeling tired.

I've done some research (and based on my own experiences with aging vehicles) and think any one of the following might be the culprit; however, I don't want to replace all of them right now since that could get spendy. I'm wondering if anyone has suggestions as to what is most likely, or if I have left something off that it might be.

Oxygen sensor
Fuel filter (never been replaced)
Electronic throttle position sensor
EGR valve
PCV valve (I know these are usually cheap, but I've never replaced it in the Grand Caravan.)

Anyone else having this problem? Any help or advice is greatly appreciated!

 

Oxygen sensor - Dont need it unless it is bad.
Fuel filter (never been replaced) - Integrate in fuel pump, and they are Huge, and will last life time of the pump
Electronic throttle position sensor - again, dont replace unless bad
EGR valve - Check engine light will come ON if it is bad.
PCV valve (I know these are usually cheap, but I've never replaced it in the Grand Caravan.) - sure, On top of rear valve cover. Do a Tune up too, spark plugs and wires, air filter, and clean throttle body.

If you've been towing a lot, Definite conside changing trans fluid.

If your Van is Flex Fuel, E85 will be fine. Sometimes if you switch back to gasoline, maybe you can try disconnecting the battery to reset the computer, might help it reset fuel trim value.

 

were you towing in OD range or D range? Towing in OD is really hard on a transmission and if the trailer was that heavy you should def service the trans fluid.

could be a lot of things but one thing I would throw out there that can be over looked is the torque converter. If the towing caused damage to the TC and it is staying in rotary flow all the time you would be experiencing super sluggish, low power, hard to get up to speed, but once up to freeway speed it would go along fine.

keep us posted on what you find.

Regards

 

Yup, only thing I would consider changing at this point would be the PCV valve for all the reasons stated. It won't help your sluggishness but It will help keep the engine from burning oil. If it's the original it's about due.

Before you throw some hard earned money at it you could try a compression and fuel pressure check. AutoZone or the like will loan you the gauges.

Are your MPGs on a downward trend? Loosing oil or coolant? Was it E85 or something else?

 

MPGs are definitely going down. Used to get about 18-19 in the city, now I am getting about 16. No oil burning that I can see from the exhaust, or when i change the oil (still right about 5 qts. coming out). Coolant seems fine.

With the trailer, it was hopping back and forth between D and OD depending on the grade. If it was flat and I was up to speed, it was in OD, but on pretty much any grade I was down in D. Went down to 2 in the really steep passes in Montana and Idaho.

I don't think the fuel in the plains was E85, seemed like it was a higher percentage. Got to the point that I was buying premium to flush the fuel system out. I know everyone says it doesn't make a difference, but it did. Definitely more power then with premium and the trailer. My engine is not the Flex Fuel one unfortunately.

I had wondered about the tranny since I've heard that towing with it can cause problems, but I will have to flush the fluid and replace as a first step. Hopefully get that done this weekend. Any tips and tricks, or is it pretty straight-forward from the Chiltons?

Thanks!

 

Because there's no drain plug I pump the fluid out the dipstick before dropping the pan. Saves a potential huge mess. I just use RTV to seal the pan. No gasket. Your manual may say to use a gasket. There are multi-use gaskets available. You'll pay a little more.