trippled
NAXJA Forum User
- Location
- colorado springs, co
I wouldn't rule out a back pressure issue. Whats the vac reading under load at ~2k to ~3k after a few seconds? Idle vac readings rarely show excessive back pressure. I have seen back pressure numbers in the 2-5 psi range that can make these 4.0's feel pretty slow.
Agreed. I have seen rich running vehicles destroy cats in hundreds of miles, not thousands. 14k IS pretty long if there was a slight issue.
Honestly, if everything else checks out I would do a back pressure reading. Most muffler shops can do it pretty cheap.
You can make a back pressure gauge super easy if you have a vac/fuel pressure gauge. Cut up an old o2 sensor and thread a Barb fittinginto it. Under 2 would be ideal and anything over 5-7 would be bad.