Hey, got another question... I have got a 2000 Durango SLT plus with 4x4 and a 4.7. I have only had it about 2 months, right now it has 81,000. I am not sure if it has had a tune up yet. But it seems like it is starting to run a little rich. I have noticed some carbon in the tailpipe. Gas mileage is so-so.. And under heavy acceleration it sounds like it is starting detonate around 3,500-5,000 rpm's, possibly in the downtubes from the manifolds. Just wondering has anyone had similar problems, and what caused it. I'm planning on doing a tune up. As of right now its not showing up any codes, and the air filter is clean. So I know its not suffocating...Thanks.......
JJ67RS

 

sounds like your on the right track. tune-up. use the autolite 3923 plugs.

 

there is a serv bul issued for the intake manifold gaskets leaking on the 318s and the 360s.Mine is doing the same thing at high rpms.