I Have a 1993 4 cylinder Dakota, 2WD. The truck runs great, no hesitation, no missing, no perceptible loss of power in low gears, just regular gutless 4 cyl performance. Lately I have noticed that my maximum speed in 5th gear is only around 55. I have changed the fuel filter, air filter, checked and regapped plugs. One thing I did notice when I removed the plugs was that they were loose. Could this loss of power be a plugged catalytic converter? I suppose I should check cylinder pressure next. Any suggestions?

 

Welcome to DodgeForum!

It could definately be a clogged cat! Drive the truck around for 10 minutes and take the temp of the cat. See if you can compare it to someone else's vehicle.