My 5.9 is so stinkin gutless on the hills at freeway speeds. It usually has to down shift and it's really anoying. I'm empty not pullin a trailer, just me and the truck. I recently installed Hughes Airgap(yes, the plenum was blown on the keg), 180 thermostat, timing set, waterpump, new belts, hoses, AIT, temp sensor. Doesn't seem to have helped at all. Everything else is stock. Thinkin of getting a Fastman 52mm TB, and a 14x3 air filter. Will it help? What else can I do? Thoughts?

 

sparkplugs, distributor cap and rotor checked?

 

You could check the cat, if the engine was pumping enough oil it could have clogged it up. The TB will help the engine breath a bit better so it will help out a little, also my old ram a 96 and the newer one a 98 are both gutless on hills both have 5.9 v8 the shift points just suck in my opinion. Otherwise you could programmer and change the parameters for the ECM, not sure if it changes shifting to much my tune is in the mail. Hopefully some other with more wisdom can chime in.

 

Yes, cap, rotor, wires are recent and were checked when the intake was out.

 

Okay, I will check the cat. I'll pull the O2 sensor and see if there's a difference. Good to know that you have the same problem on the hills. I plan on getting a custom tune as well at some point. The shift points are a bit wacked.

 

+1 on checking the cat. I think the owners manual states to turn OD off when going up hills. Of course the main problem is your gears. And you are not the first person I've seen complain about power after installing the Air Gap. More mods are needed. Like better flowing exhaust, gears, cam and heads maybe, to bring it all together. And a good tuner like SCT.

 

I had the SAME EXACT problem.....ended up being the cat was clogged...

Had duel exhaust put on it....and WOW whata difference!! Even more power than when the cat was'nt clogged!!!

i'm also up to 14.7 mph from 11.4

 

Wow, wouldn't riding a bicycle be faster. (sorry, couldn't resist.)

 

Echoing others. Yepper with all you've done it's time to take a hard look at your exhaust. You need to pull the plug on that beast and let'er breathe. Your cat is probably clogged but when you replace it look into something a bit bigger which will compliment your existing mods and I predict you wont be sorry. Also if your gears are too long even a 1000 horsepower wont help much. For big tires you need the right gear ratio or it's lame.

 

I am surprised it is so gutless with the purple ice