Well I have 99 4.0 auto 4x4 ext cab, I notice a while back that it bogs down when mudding.. 2wd or 4hi doesnt matter.. It doesnt get to the point to shut off, but I have to let off and accelerate again for it to start moving again.. It just lacks power in wot..I was leaning towards my cats being clogged.. has anybody had a similar problem? Help Appreciated..

 

The cats would be the last thing i would think of. What rpm's are you getting too?

 

mine does the same thing i'll hit the mud at around 4000rpm, and after the tires start slipping it will go down to about 2000rpm, i can put it to the floor and never get above 2000rpm

 

Exactly what mine does..The more I floor it the lower the RPM's.