Hey guys, im a lowly FNG but i have read and read on your forums. You seem like a knowledgeable friendly bunch so i have decided to join and maybe, in time, i can be knowledgeable too. I have never had any trouble with my 98 ram 1500 5.9 (145K miles) until a couple of months ago. On my way home from work, at 0300, I got a check engine light accompanied by a loss of power and vibration. I pulled over immediately to make sure i had oil (truck has burned 1qt between oil changes since i got it with 22k miles). My oil level was fine, so i pressed on. The next morning i took it to autozone who read my codes, P0308. SOooo I bought new plugs and wires. My #8 plug looked like hell, burned with sintered metal on it. The new plugs and wires smoothed the truck out a little but the vibration wasthere, the lack of power... there, check engine light.... still shining.
Then i found dodgeforum.com. I have since checked my compression, rerouted my spark plug wires, disconnected 1 fuel injector at a time for RPM fluctuations, and am currently cleaning fuel injectors and rail.

My compression readings were: 1) 130, 3) 140, 5) 127, 7) 145, 2)145, 4)147, 6)125, 8) 167. I got these readings with the engine warmed up, 10 revolutions of the engine, plugs out, fuel system still spraying(DUMMY).

I was unable to discern any difference of engine speed as i unhooked 1 fuel injector at a time. I dont know if this is because the stock tachometer is not precise enough to show the variation or if there are other factors. Idle was 625-640 regardless of if they were all hooked up or which one was out at any given time.

There is a bunch of doodoo in my fuel rail which i have sprayed out to the best of my ability (avoid getting B12 on your face, no bueno), i have sprayed out my injectors as well as i can. I will be putting them back in momentarily and testing.

I have read a lot about the likelyhood of the plenum gasket failing, that is my next step.

Ideas?

 

Take a look down your throttle body, if there is oil pooled inside then it's the plenum. Did you change your plug wires and cap and rotor as well?

 

Welcome to DF.

You may have other issues going on, but your plenum is most likely one of them.

 

also, for what it's worth, and i didn't read the whole article btw, but there's a TSB about how to route your spark plug cables. Apparently if you don't route them a certain way and use cut tubing around them, you can get misfires, pinging, or rpm fluctuations. Just google it, the TSB is everywhere.

 

Its in the FAQ section.

 

It looks like pulling the fuel rail off and cleaning all the doodoo out of there (rusty yuk) and out of the injectors fixed my troubles. I have not changed my rotor and cap. I have changed plugs, wires, and done the plug wire reroute. Inside my intake looks pretty clean. So for now i think the truck is working pretty well. It runs smooth and no more check engine light. When I do (apparently it is a when, not if) have to change my plenum gasket, is there a neato intake upgrade or should i stick with the kegger? Thanks fellas.

 

Yeah there is a neat intake upgrade and it comes with a shiny price tag of 600 from hughesengines