I have a 94 ram 1500 5.9L 65k miles cold air intake, hollow empty cat converter, new plugs, new wires, 180 stat, new pcv valve, new CC breather. Plenuem is good. Oil and trans fluid is good..All upgrades were done months ago. And the last couple days the truck has been running weird. Almost lagging. Like something is holding it back. I've checked the brakes they seem to be fine. I don't see any calipers hanging up. Even when I'm coasting down a hill it seems to be holding back. Something is robbing my power. Any help would be appriated. Truck idles fine and doesn't miss. It just started out of no where. It's very subtle but definitely noticeable

 

Check your fuel pressure.

Might also put it up on jackstands, and spin things by hand. See if you notice anything binding.

 

I just put it up on Jacks the tires spin good. I didn't check the back. It has a limited slip rear so idk if I'll be able to tell. And I'm resetting the fuel trims right now. I disconnect the battery and gonna let the computer reset. It hasn't been reset since all the upgrades. The only thing I can think is bad pully maby. Or something with fuel pressure like u said. I know my fuel gauge went out like a month ago. How do I test the fuel pressure?

Update. I put the truck in neutral and jacked the back up. I can turn the tires but there's a bit of resistance. It does have a limited slip rear so I'm not sure how free they should spin. The front spin fine. The rear I can just bearly turn them by hand. I was only jacking up 1 side at a time

 

Jack up the entire rear, put the trans in neutral. Then try and turn them. Given you have LSD, the resistance is correct for the method you used.

Block the fronts, so the truck doesn't try and get away.

 

Okay after disconnecting the battery for an hour. In attempt to reset the fuel trims. I hooked to back up. Started it. Let it completely warm up. Took it for a short drive and it completely drove better. It was a short drive but it was a ton better.. can someone please explain why? I don't know if it's a permanent fix but for the short time I drove it . It was way different. Can someone tell me why before it was running like crap. And now after disconnecting the battery for a while and resetting it, it changed. Why did it run like crappie before and better after

 

Can't really diagnose it without further info, could be a sensor going bad, could be that the fuel trim was incorrectly set. If it happens again, take note of what everything is at; load, engine speed, vehicle speed, engine temp, if the a/c is on, any DTCs that become present. You can retrieve codes on obd 1 by cycling the key 3 times and counting how many time the check engine light flashes. If you can get engine vacuum readings, that can help a lot.

 

Throttle Position Sensor maybe? Maybe one of the mods got that messed up, resetting the PCM let it adjust back?

Shot in the dark.