I know im beating a dead horse on this as its all over the internet, but i have to ask have you guys used the 3923's and if so what did you notice as far gas mileage ? My 98 5.9 last year used to get 13.5mpg city, and its been slowely going down my engine pings occasionally as well sometimes it does, sometimes it doesnt when i give it hard excelleration.

So hense why i tried the autolights, but they didnt seem to help at all with the pinging. Now however it seems my MPG is getting lower and lower and i can barely even get above 11mpg on the computer reading, and through the tank 2 days ago i measured 11mpg exactly after 140 miles in the city. Is it these autolight plugs that are contributing to the loss in gas mileage ? Im also not sure, maybe it could be the engine oil im using ? I also recently decided to try that Rotella T6 5w-40 after many recomendations. Not sure what to think of it over the 10-30 dino castrol i was using. It did quiet the engine down slightly but then it wasnt really noisy to begin with.. Can a synthetic oil like T6 also lower MPG ?

Plenum asside i already know mine is most likely going bad despit the pan front to back being sparkly clean, and the pressure test passing. But my Q is about these spark plugs.

I have 8 brand new Champion RC12LC4's. Should I put them in ? Oh and i also just got to replacing my rotor, cap and ignition coil... The rotor and cap were horrible so much corrosion that the metal points in the cap were half way worn away and looked like a battery terminal. Most likely the original cap/rotor and coil.

http://i1083.photobucket.com/albums/...2/IMAG0246.jpg

http://i1083.photobucket.com/albums/...2/IMAG0245.jpg

 

If you pretty much KNOW your plenum is blown, what is the purpose of this thread? Fix the damn thing first, than let's talk. Geez.

 

Well I dont know if its blown or not, the TSB done by the dealership said it was fine, and looking down in there with a mirror it looks fine. So i dont know why im pinging if the dealership said im good and looking myself it looks good.

 

I noticed pep and my ping went away with the 3923 and 180 tstat

 

The TSB is useless and the fact you have pinging confirms it for me. Keep waiting, so your problems snowball and you'll have other major more expensive issue's. Good luck there guy.

 

Im not waiting, i already have the pan, i just need to wait for the next pay checks to come in so i can buy the torque wrenchs i need that i dont have. I dont exactly make thousands of $ every month

 

I can understand about working on a budget. I've already got my plate and gaskets but I'm planning on doing the timing set and waterpump also when I do the plenum project. Probably will go ahead and do my oil pan gasket and rear main seal at the same time too. So I'm still in the process of getting all my parts together and that takes a while. It's actually driving me crazy right now. Due to certain family financial situations I am on more of a budget than I usually am and I'm chomping at the bit to get this project done but wait, wait, wait...UGH!!!

 

Well it needs replace. (and since you have the plate) When you can, do said replacement. Meanwhile, why waste money on plug's? That BTW, you can look in the FAQ/DIY section for everyone's opinion's on plug's. WHich will be for performance reasons, not MPG's. Fixing the plenum and doing everything that you have read on here is what will give you better MPG's.

 

If you live in the states you can go to Autozone if you have one and rent torque wrenches.

 

the same exact made in tawian wrenched they sell at advance are $10 at harbor freight under the "pittsburg" tools brand....I have a couple of them and they work well... good enough to do this job anyway. If money is that tight sell the aluminum plate you dont really NEED and just use washers on the stock bolts or get shorter bolts and a new gasket and fix it the way dodge dealers would...