So 2001 dodge ram. 5.9 v8. Gas mileage dropped from 14mpg to 8mpg. No high end power under load. Just stalls like it's about to run out of gas. Doesn't over heat. Got a worsening rattling in my valves. Getting codes p0443 and p1281 and p1495. Now my ecm has already had an issue controlling the alternator and I had to bypass that with an external controller. Could this be an ecm short or do I have another issue. Longer I run it the worse it gets. Park it for a while, gets better

 

Read the plenum sticky. You have all the symptoms.

 

I've got the Hughes plenum on there. But that doesn't mean the gasket isn't blown. Everything else fits. Urg

 

I would also check you cat. No high end power and stalls out could mean your cat is clogged or is becoming clogged. Pull your upstream O2 sensor and see if that makes any difference in the way it runs.

 

I pulled the intake off 6 months ago. Put a new plenum gasket on it bc it had oil in it. That's gasket number two. I also changed the pcv valve. Will permagasket help there

 

But the cat being clogged wouldn't increase oil consumption and fuel consumption would it?

 

P0443 Evap Purge Solenoid Circuit
P1281 Engine is Cold Too Long
P1495 Leak Detection Pump Solenoid Circuit

What temp does your truck run at? Looks like you have some vac leaks also.

 

The added use of fuel and the oil going down the exhaust could clog your cat real easy. That is what happened to mine. I can't tell you why or how but it doesn't hurt to check and it only takes a few minutes. I could be wrong as I am no expert.

 

The temp is bc of a 165 thermostat. I've tried to track down every vacumn leak I can find. We'll state quit doing emissions testing so I feel a straight pipe really soon. Way cheaper than a cat. That will solve that problem. So I after that it's plenum gasket and pcv valve. I don't think that Hughes plate is cracked.

SOMETHING ELSE I FOUND:
Does worse on higher octane gas if that helps any

 

running without a cat brings its own set of problems with it, get yourself a magnaflow high flow cat.