So Ive thrown a code a few times, missfire on cyl 8, after either, cruise control on the highway goin up an overpass, or just getting on it for fun. each time it pings like crazy. I went to school for motorcycle tech and have tuned a few bikes that like alot of gas at a certain rpm/throttle position. I was told by a few people that i just need a tune up (its been quite some time since she's had one). what do you guys think? Hopefully i will get new speed sensor before the weekend, 3 days off planning on new plugs, cap and rotor and new ball joints installed.

edit: Ive got a CAI and a catback dual exhaust if that helps anyone.

 

A misfire on #8 is usually the sign of a clogged or clogging cat due a bad plenum gasket.

 

Sounds just like a blown plenum. Is your truck using excess amounts of oil? Get a flashlight and take off the breather box of your truck, look down the butterfly valves and see if there is a oily mess if so, you need a new plenum plate and gasket.

 

Doesnt go through alot of oil (about 1/2 qt every oil change) but I will check the butterflies sometime tomorrow. spent my 3 days weekend fighting a cold and got called into work to help with recent death threats on the phone due to a local drunk idiot ex employee not wanting to follow policy(cant say more than that but you might be able to figure it out by where i live) Havent been on here in a while due to a recent crack down of internet policy at work. they have since stopped caring...again. I kinda figured I would have to fix the plenum eventually. ive put 80k on top of the 100k on it when i got it. that and the tranny will need to be rebuilt soon, i think. also would it be a good idea to do a double roller timing chain?

 

Most on the forum recommend new timing chains while doing the plenum, might as well do it since your in the neighborhood.

 

Good to know