1998 Ram 5.2

[heyJeff-dodgeThis]

Still Stumbling, Popping and Back Firing and Jerks When Accelerating. I Think it is The Plenum Gasket and Plate.​

As stated above I think it is inevitable that i replace the plenum plate and gasket with everything in the kit including the bolts with locktite ect. Replaced the coil, air filter and things that are common.
Replaced the 6 and 8 plugs. I really just was putting off the inevitable. I am getting things ready to replace the plenum plate and gasket and I think I will put new valve cover gaskets on it. The motor was rebuilt at 80k miles. I am getting vacuum when I pulled off the the PCV vale and plugged off the other side as well. I am getting a lot of vacuum from the vale covers. I took off the breather, (that I hate) and looked in the throttle body and there pooling in the bottom of the plenum. All signs of needing replacing from everything I have been able to research. Any other ideas would be great?

While I am going to all this trouble, I want to put in anything that is reasonable to replace while at it. Valve cover gaskets will be replaced and I will check the injectors after I learn what to do to check them. It is going to be difficult but doable and I want to save anytime I can by lining up other parts that might be good to replace? What do you suggest I do while I have it this far down? Things like sensors, gaskets, or really anything within reason. I have $300-$400 to put in extra parts (IF) it makes sense. I have another new cap and rotor button if I don't like the looks of what is in it.
I like the truck and want to get it shaped up to do whatever I need to.
It has 230k miles and was rebuilt at 80k miles.
Thank you for any help. I know you guys have a lot of experience and that why I am asking the pros. Thank you in advance.

 

[Yeret]

One of the best pieces of advice I could give is be very careful with the intake manifold bolts. They're torque-to-yield style, they're very easy to break, and you cannot reuse them once they're out. Depending on where you buy your kit, it'll come with new mounting fasteners to use. When I went pull my manifold to do the plenum repair, I manged to break 2 of the buggers, one in each head (of course!).

Absolutely make sure the repair kit uses a Fel-Pro gasket. You get what you pay for strikes hard with gaskets, and unless you feel like doing this job again any time soon (you won't!), you'd be best to buy quality. There is also a very specific torquing sequence for the plenum pan. Don't cheese it, or you might find yourself doing it all over again!

Throttle body will probably need a good cleaning and removing the intake manifold is gonna give you a great opportunity to do a thorough job. Don't forget about the IAC port; it gets dirtier than you think. You should also replace the TB gasket while you're in there (again, go Fel-Pro).

Since it'll be out, you might wanna give the manifold itself a good cleaning if it's dirty. Depends on whether or not you care about aesthetics. Since you'll have to at least partially drain the cooling system, you might consider replacing the thermostat and upper radiator hose. If you drain the entire system, do the lower radiator hose too.

 

[heyJeff-dodgeThis]

Great advice that confirms several things for me. I have the Felpro in my shopping cart and I definitely will be cleaning everything I can while I can get to it. There are so many things that can barely be accessed while this is off. Any other sensors that you can think of to replace that would be worth it while I'm in there? I don't know what a lot of them are.
I have seen about the "H" torque pattern so I'll be very careful. I really appreciate this and any other advice you have.

 

[Yeret]

Only sensors in the manifold are the intake air temperature and the coolant temperature sensors. You can replace 'em if you wanna be nitpicky, but they're pretty easy to do with the manifold in place.

If you do replace any sensors, go either NTK or genuine OEM. They'll cost a bit more, but you get what you pay for is well in effect; I've got a pretty rocky track record with cheaper brands.