This is insane according to the overhead display. How is this possible. It's like 32l/100km. Anyone have any ideas? Just city driving but still. Also seems to have a miss at idle. No CEL though. Also when I rev the motor by hand I can hear the PCV rattle for a few seconds.... I tried to get the PCV out but the rubber grommet is hard as a rock. Anyone know the part # for the grommet as well? What could cause this horrible mileage? BTW this truck is new to me within the last 4 weeks. I did the plenum and thermostat.

Thanks

 

PCV will rattle, that's normal.

Gas mileage is atrocious though..... Pull a couple spark plugs, see what they look like.

 

I will, pretty sure they're covered in oil and fouled from the plenum leak. The PCV looked to be original so I am thinking maybe the spring is shot. Figure might as well replace that as well while I'm at it

 

What engine ya have in it? Is that the 5.9? If so, some of the parts are going to be aftermarket only. I WOULD get a genuine Mopar PCV though, they are actually the correct flow rate, and they are cheap. If you don't know the last time the truck had ignition parts replaced, go ahead and do them ALL, plugs, wires, cap, rotor. It'll likely help some, but, I doubt that's gonna be the end of the problem. O2 sensors are likely shot as well. (and probably original....) And THOSE have the MOST effect on fuel economy. If you wanna replace 'em, or, at least, the front sensors, go with Denso, or NTK, the cheap ones cause more issue than they solve.

 

I'll look at the records but I believe the ignition components were done about 20,000 kms ago. I bet the o2 sensors are original as well. Good to know about the pcv valve although in canada I bet I get bent over no lube for it. It's the 5.9. Seems low on power compared to my old one years ago although my other vehicle is an x5 50i so that could be why

 

Don't expect BMW performance from your Dodge.

I would wonder if the cat is clogging up as well. Burning oil doesn't do it any favors...... But, that said, even when it was NEW, the engine just wasn't as powerful as you would think.... The 5.9 was ok in my 96 2500, the V-10 in my 98 though? Yeah, MUCH better. (except for the gas mileage.....)

 

yeah I hear you I just remember my old RT seemed quite a bit and my old ram both with the 5.9 seemed to have more juice. I did find a vacuum leak at the PCV valve where it goes into the grommet so that's definitely an issue. I can hear it hiss until I move it into a certain position. Probably needs o2's and plugs too...

 

Wow my 5.9 is like a , well speedy as a matter of fact I had the original muffler get a large crack and start doing the Pss pss ps s thing so I replaces it with a 14" Jones resonator (Through flow) and 24" of pipe and it seriously lit a fire under it now, My G friend keeps taking off a spinning the tires and asked why it now does that all the time LOL
Im at we over 254K (miles) But I did have 140 PSI even all 8 cylinders when I checked it as well as did a Port match and clean up /Valve job on heads in 2019 when I replaced the head gaskets when the neighbors owned it so that may have helped a lot as well.

 

I replaced the grommet and pcv valve although with a cheap amazon version. Seems to have more power but now I can literally hear the pcv valve buzzing/rattling at idle from the cab with the window open. I knew the cheap pcv wouldn't work but I got a grommet which I needed. I'll try the OEM pcv next and see what that does. Then it's pull plugs and check those.

 

When was the cap and rotor replaced last? When you had the plenum off was the time to replace them(easy to get at).