I just wanted to add my two cents on here-and say thanks! lol. Last year I bought my 1995 Dodge ram 1500 318 engine standard 5 speed. The idle was very unstable-and ran very poorly. For many agonizing weeks I couldnt figure out what was wrong with it, then I found this forum and read about the plenum intake problem. Sure enough, I had it. I tried replacing the gasket and put it all back in, but still had troubles after it warmed up. Turned out that the manifold was also warped, allowing vaccuum to escape! The intake was covered in oil. I took the advice on here and bought a Hughes intake. Yes, it fixed almost everything. ALMOST. It still had this problem similar to what is posted here-it would run fine for a while, then it would run bad. If it did this while I was idling at an intersection, white smoke would pour out from under the truck, but then stop as soon as I take off. I used to get a code that said it was the cam position sensor in the distributer. So I take the distributer all apart and clean clean clean. I reset the computer. Well it started doing that again, only now the computer throws a code 27, which is fault in the injector circuit. So I check, replace old wires, clean connections, terminals, etc. fixed it for one day but not much power. Back to doing this all over again now and even more often. Tried recleaning connections but made no difference this time. I had the idea to close off the fuel evap canister, because usually when it messes up I can smeel something that smells like old gas around the canister. Well closing THAT off doesnt work either. In fact its worse now. Im next trying the catalytic converter check. Thats my only hope I have left. UUUGGGGHHHH
Anyways, from my own experience, when my plenum went out, the idle was very unstable

 

Mine seems to idle fine other than one time after it was giving me trouble on the highway. I'm hoping my cat is the only thing that's bad, although the truck does have 200,000+ miles on it. I haven't noticed any pinging, just the backfiring on the highway around 2000 RPM after it heats up. I'm tempted just to cut the cat off and run the piping for dual exhaust and throw two flowmasters on it.

 

Kb, if you remove the cat, what do you do about the oxygen sensor? Mine is installed into the cat. Is there an aftermarket pipe that has a hole for the sensor?? By the way, I just redid some of the vacuume lines on this truck-and so far its running great. There is evidence whoever had this truck before over heted it a few times

 

On mine the O2 is installed in the exhaust pipe just before it goes into the cat, not sure what to do with the sensor that's after the cat though. I also just replaced the vacuum line on mine this weekend that goes from the engine bay to the vacuum switch on the transfer case, it had melted up by the engine when the prior owner had it, looked like it had gotten pressed against it somehow

 

Jegs/Summit both make an "off road" Y-pipe, that has both bungs for the O2's. If you don't need the rear O2, (95 and older trucks) just put a plug in it.

Other alternative is, any exhaust shop should be able to put a couple weld-on bungs on there for ya.

 

Mine is a 96 so it has the O2 sensor thats after the cat, what im wondering is what people usually do with it if they do a cat delete. Also since I plan on making it dual exhaust I'm wondering if i can just run two separate pipes with mufflers or if I also need to add a "H" pipe in between them? Im gonna do some searching on here and see what I can come up with. Any ideas are much appreciated though.

 

I was once told that putting an "H" in the exhaust system greatly increases torque for some reason. I don't know if that still true or not here is a discussion on it with Broncos
http://classicbroncos.com/forums/arc.../t-179563.html
Thanks for the advice, Im going to look into summit about that Y pipe