Hello all,

My 1995 5.2l is in need of a plenum I'm pretty sure. After researching I am confident that's what it is. Rough idle, terrible MPG, excessive oil consumption, lack of power, pinging. It also needs plugs and wires, cap was recently replaced. The truck just rolled over 100,000 miles this fall. First owner was my grandfather and I took it over 9 years ago with 37,000 miles.

I am unsure about doing this project myself or hiring it out. Its cold here in Vermont, and working in my unheated garage doesnt sound all that fun. I got a quote for the plenum alone, and they said $450 if all goes well. If I did it myself, I could change plugs and wires, timing chain, (water pump has about 12,000 miles on it) and have some money left over for upgrades.....which leads me to my next question....

Hughes Plenum Kit. I was thinking the $159 with Felpro gaskets. But what about the Hughes Air Gap? Completely eliminates the plenum, improves MPG, and power. My truck being a 1995, they told me I will need to plug my EGR valve on exhaust manifold and may cause a check engine light that he claims will go away on its own. Is this true? I dont normally exceed 2500 RPMs often, unless it downshifts out of overdrive on the highway. From what I read you need the RPMs to get results with the Air Gap.

Thanks alot and please leave any comments or advice I will be continuing to research!

 

Then you don't want the air gap, It is designed for mid to high rpm use. Stick with the kegger and the Hughes kit.

 

You don't really need the hughes kit for the plenum, (though it is good peace of mind....) In reality, you can just change the gasket, with a GOOD QUALITY gasket, and use shorter bolts. (or, cut the nubs off of the end of the existing bolts......) Follow the proper torque sequence, (and use the blue loktite they suggest....) and it should be a permanent fix.

How cold? If you haven't done it before, figure on spending an entire weekend on the project, and that's if you don't run into trouble. The corner manifold bolts like to break..... the heads of them just snap off, so there is plenty sticking out to work with if it does happen. I just use a pointy stick to clean the crap out around the base of the bolt, where it goes in to the head, hit it with some PB Blaster, let it soak for a bit, grab ahold with vice-grips, and wiggle the bolt back and forth, while tapping on the end of it with a hammer. Usually, a couple minutes of that, and they will break loose, and thread right out.

Another problem area is the oil pan gasket, where it meets the timing cover. Gotta be careful when pulling the timing cover, tipping the top forward, and making sure it doesn't take the pan gasket with it.... can be fun. (two people for this exercise REALLY helps.)

Make sure to get a double roller timing set. Don't just replace it with another morse-style chain. They are way to prone to stretching.....

Hughes intake in and of itself simply isn't worth the expense. If you were doing cam, heads, headers, etc as well, then yeah..... otherwise, its a fair bit of money, for not much benefit. You will lose some low end grunt, but gain power in the mid- and upper- RPM range. Not necessarily where you want it in a truck. (more mid-range is cool, but, getting there is rough. )

 

Thank you for the detailed response. I have never done this project before, but I do think it would be fun to do. I may try to get some heat set up in the garage to make working conditions a little more enjoyable.

I will probably go with the Hughes plenum kit, but will pass on their intake manifold. When doing the timing chain, do I need to remove the water pump where a new gasket will be needed? I would like to get everything ahead of time so I dont need to make many trips to the city to get parts. I wonder if there is a thread on here that has "all the tools needed for the job". Going to read more into the sticky plenum thread. Also, do you recommend a place to get the timing chain you speak of?

Thank you

 

The only special tool you need is the fuel line release tool. 3/8ths, as I recall. Local parts store will have 'em.

Yep, water pump comes off to do the timing chain.

The rest is just the usual hand tools, and then cleaning supplies for gasket surfaces and such. Air tools make that part of the job easier, but, aren't a requirement.

I just went to my local parts store for the timing set. They can likely order anything ya want. I needed it RIGHT NOW, so, just took what they had on the shelf. SA Gear, .025 pitch, timing set. Under 50 bucks. Been in there a couple years now (on my 96) and runs great.