A month ago I bought a 2003 Dodge Dakota automatic pickup 3.9L V6.I noticed that it really didn’t have a lot of power and i brushed that off because of the engine size.It only got worse with it at 60 mph the tachometer is at 4 grand before it shifts and also while driving over the small mountain near my house (all paved)I average 20 mph with the pedal to the floor.I had a tune-up done plugs,fuel filter,air filter,oil change,all fluids filled,etc,trying to find the problem to no avail.the transmission shop figured I had a backed up exhaust system so I went out and replaced the catalytic converter,muffler, and had duel 2 1/2 in. pipes put on.It still didn’t fix any thing.I’m at a loss.I’ve been told it could be bad coils or a jump in my timing chain or a a multitude of other things.Someone Please help!
Some more info would help.
Does the engine idle smooth?
In neutral, if the engine is revved, does the engine rev up in a sluggish manner or does it seem somewhat snappy?
Some possibilities here.
One is that maybe it’s possible the ignition timing could be off since this truck uses a distributor. When setting the timing a test plug is generally grounded or jumped. Failure to do this will give an incorrect reading.
If the timing is retarded because of this, the mileage will suffer and the engine will be a gutless wonder.
Whoever did the “tune-up” should have checked this.
After that, maybe there is the possibility of a transmission slippage problem, but since you mention trans shop I assume the trans has been ruled out?
I can't tell you what it is, but I can make one additional suggestion. If the converter is clogging up, that is exactly the result. The converter may still be under warranty.
If there is a problem I would think the SES light would be on. Have the codes been checked?