Hey, I'm a new guy here. I have been reading this forum for a while and enjoy it, it has a lot of good information. I have not done anything on my profile yet, but I plan to. I usually look at the forum at home, on my blackberry and do not know if I can do that on there or not. I am at work now (lunch break). Anyway, I have a 1998 Ram, 360, auto, 4 X 4, 136,000 or so miles. I have had it since brand new, purchased in October 98. It is almost totally stock. I recently had to have the transmission rebuilt at 132k. I knew it was coming, having heard about Dodge transmissions since I purchased the truck, so I wasn't too disheartened. However; after reading here, I bet my plenum is blown as well. Sometimes this site is depressing.. There is a mist of oil inside the plenum, no visible puddles. I would think this is somewhat normal with the mileage, though, as the pcv valve would emit blow-by gases into the intake. The truck burns less than a quart of oil between oil changes (3k). I have very little spark knock, will do it occassionally in OD with AC on going up hill. I get about 12 mpg, doesn't matter if I'm on the highway, in traffic, pulling a trailer, etc. It only got about 14 mpg new. I do hear a sucking noise under accelleration at 2200 or so rpm's that is not audible at lower or higher rpms. I do not know if that is related or not. Haven't found any external vacuum leaks. My question is, if it is blown (most likely, I know) the truck is running fine and getting average mileage so why would I not play ostrich, stick my head in the sand, and wait for it to develop a leak with noticeable driveability/oil consumption issues. Would I not be crazy to tear into it just because I suspect it's blown, even though it doesn't appear to be hurting anything? Didn't I read somewhere that the majority of magnum engines in these trucks probably had this internal vac leak from the factory? Anyway, long post and I know you guys are tired of the plenum deal probably, but if you're really tired of hearing about it...don't read the post or respond, right? Forgot to mention, changed plugs at 100k, never changed plug wires or rotor. Plan on doing plugs, wires, rotor when I get a day off work alone (w/o kids).

 

Well what will happen if you ignore it is the following...

Fouled plugs
Junked cat.
Fouled O2

I didn't think mine was that bad either. Last night I got the intake off and one section of the plenum gasket was hanging out the side of the pan...

 

It was a defect from the factory with the plenum all gas 94-2001 rams will have this gasket blow out...you need to get a hughes or APS plenum kit. If you just replace the gasket it will blow out again in no time. Its actually a pretty easy job....id recommend taking your manifold to machine shop and having it cleaned...and do the kegger mod...i did this and there was a great difference...i have a 95 360 with 200367 miles...i get 14 city, and around 17 highway, and thats no joke...but ive put alot of new parts in it, and i have 4.10 gears in the front and rear diff...dont know if that actually helps my mpgs...

All in all change the plenum no matter what, even if its not blown out yet, change it with a hughes or APS kit...then you wont have to worry about it again.

 

I figure if I replace plenum, I'll have to replace plugs, cat, and 02 sensor anyways after running seafoam or something similar to clean out. At any rate, you goys won't let a brotha be in denial will you?

 

plenums an easy job IMO...and yes its a perfect time to do plugs, wires, cap and rotor....also i still have stock 02 sensor and CAT, and my truck still runs perfect, so you may not have to worry about those...and i have 200K

 

Until you find a broken intake bolt...

 

Those gears do help with those slightly larger tires. I hope to increase my MPGs a bit after I change my gears to 3.92s, but if all I get is better power on the low end, I'd be happy.

+1.

 

Word. I replaced cat several years ago. Was rattlin like a mean snake. I changed out the heater core in one night when the kids and wife were outta town. As I recall it was a very cold night so after I got the truck driveable, I drove to ye old beer store with the heat on and most of the dash trim still in the garage. Was strangely enjoyable, except I did it alone and was scared the dash would dissintegrate as I was wrasslin it out of the truck. If anyone has done both the heater core and the plenum, which is a larger pain in the nether regions? I plan on using the hughes kit if/when I do it. Gotta find the time. Also, that airgap looks damned tempting if you can really gain the mpg's stated. And the added power wouldn't be something I'd snub my nose at either. Anyone have any airgap mpg increase experience? Typing on a backberry is a *****.

 

Thats pretty darn good typing for a BlackBerry.

Cut the airgap MPG claim in half, and MAYBE, if you keep your foot out of it, which you won't because of the newly discovered extra HP and torque.

 

Hmm..cut it in half...that would give me about 15 mpg. If I really thought I could get 6 mpg increase, I'd have 18 mpg, which would be worth the 6 bills for the airgap for me. I'm driving 60 miles a day now, is my only truck. Leaning towards just the plenum kit and new plugs, wires, etc. I work at a scrap yard and could easily get my hands on some good 1/4 aluminum plate. Is also where I got my "new" radiator and the vacuum servo deal to fix my cruise. Will have to search the threads for making your own plate. Does anyone know if the 318 intake is the same as the 360? Have a scrap truck at work with 318 that I set aside for parts. I could get the intake off it and make a plate for it and have it ready to swap out ig they're the same.