I hate to make my first post on a forum one asking for help, but I need to get some ideas from the Allpar community.
My family has owned a 2002 Town and Country since new, and it has had minimal problems until recently. In the last month, the mileage dropped from an average of 18.9 MPG to about 14.8 MPG, the car was running extremely rough on start up, and power would not "kick in" until about 4100 RPM.
Naturally, we assumed this was because we had had the same spark plugs in the car since new... for over 215,000 miles. I did the job and replaced all the plugs, and expected a brand new engine. While I was back there, I also noticed that the rear exhaust manifold bolts were almost all lose, and there was soot on the spark plug wire on cylinder no. 1. For about 3 years, the car had an exhaust leak that made it sound like a lawn-mower. It didn't affect mileage or driveability, so we had just ignored it. Discovering THAT problem, I re-tightened the exhaust manifold bolts, attached all the plug wires and started the car up.
The lawnmower was no longer present under the hood, and the car started quickly with 0 roughness after start up. I took it for a spin, but found myself upset when I noticed that the accelerator still appeared to have dead spots - especially at low rpms (up to about 3500). For example, flooring it from a dead stop resulted in less than stellar performance, and the power would still not really "kick in" until about 4100 RPM. Gas mileage is still just as bad, and I notice at low engine speeds and low throttle, such as when accelerating slowly from a stop in a 25 mph zone, the car surges, noticeably. It is as if I am taking my foot off the gas, then putting it on, taking it off... I also notice a lack of power on relatively flat road around 50 MPH, the car needs to shift down a gear to have any real power - I expected more torque from this engine!
We have a '97 T&C with the older 3.8, and it definitely has more balls right now than our '02, so I know something's wrong with the engine. The other thing I have noticed is it seems to be running slightly rough, very subtle but definitely present. You can also see it when the engine is at idle with the hood popped.
This car has never thrown a Check Engine Light in its lifetime. The only issues we have really had were with a sensor for the airbag being bad, and recently our ABS light has come on at highway speeds, but then goes away. No lights are on the dash right now.
My first thought was to clean the MAF sensor, only to discover that, indeed. these engines utilize a MAP sensor. I thought the O2 sensors may be bad, but those are expensive and difficult to access just to throw at the car. We did not change the spark plug wires, but we are going to replace them with a set of Bosch wires from AutoZone tomorrow. The new plugs I put in the car were the correct Champion Double Platinum plugs. The old plugs were almost completely eroded, and yet, I barely noticed a difference in the way the vehicle runs.
Any help would be greatly appreciated! Thanks much for reading this!