95 SLT V8 4x4

I just had the transmission rebuilt and the truck was running really well. Then I started it after sitting for a couple days and the idle was pretty rough. Then i tried to drive and it runs pretty rough. Even after warm up. Checked for codes using the key flip and none are present.

IAC is new and throttle body is clean
PCV valve is new
No codes present

I'm going to reset computer and drive it to get new plugs, check the cap and rotor.
I feared it was the crankshaft position sensor but its not a random cough and it starts ok. Maybe injectors? Need some help diagnosing before i spend time and money chasing the bug.
thanks:

 

I went and got a mopar pcv valve because its true DO NOT USE AFTERMARKET THEY ARE CRAP!
sorry the 8 dollars hurt

I also tried replaced the grometts for pcv and breather filter along wit a breather filter. The inside of my valve covers are crusty sludge. Soon ill put new valve cover gaskets and clean those up. New air filter too.
No change with the new pcv as far as idle goes.
I also checked for vacuum leaks using carb cleaner and spraying all vacuum hoses as well as around injectors and intake. No changes in idle so I don't think I have vacuum leak.
Tomorrow I'm going to change the plugs and inspect the cap and rotor. Fingers crossed that helps.
Side question, I would like to soak my motor in atf or kerosene overnight then drain the next day to clean out all the gunk. Anybody try that with there 1st gen?

 

Look down into the intake plenum (motor off, open the throttle via hand and look past the blade, helps to use a good strong flashlight).

If it's oily, you have a blown plenum gasket. This is a known problem with the Magnums based on the LA motors (like the motor you have); the quick fix is to replace it, the sure cure is to use a plenum fix kit (like the one Hughes Engines sells, http://www.hughesengines.com/Index/p...z&partid=27091 , but they're not the only supplier of these kits) or just weld the sucker together. (I'd use the Hughes kit if it were me.)

RwP

 

Here is an oil change method I learned on another site. YMMV.
Warm up the motor. Drain the oil. Remove the oil filter and drain it then put the dirty filter back on. once the oil is drained put the plug back in and add 1/2 the recommended amount of new oil and 1/2 quart of diesel fuel. Drive it as normal or more if you only commute a little ways. I drove for about 100 miles nonstop when i did it on the Dak. Drain the oil while still warm and replace the filter with new and add new oil. That will clean up old valve seals and probably loosen that gunk in the valve cover.
I happened to notice I had oil on the plenum after I did this and I had already done a Hughes engines kit. I put a filter in teh PCV and the driver side blowby filter to the air cleaner hoses. Turns out that was blowby that got past the driver side blowby filter and the aftermarket air filter I had. The Mopar PCV is not letting anything by. I posted pics of it on here somewhere.
Edit-here is that link with the pictures; https://dodgeforum.com/forum/1st-gen...lenum-kit.html

 

I changed the plugs. It's funny what others pay for mechanics to do. I found three of the plugs had double washers so the old washers were still in the holes. I checked all ports with a magnet and got three. This probably didn't affect the idle but it would defer proper fire. So after the plugs she runs fine now. A mild rough idle probably due to the plenum. This winter break I'll have time for that along with cleaning valve covers, valve seals, distributor seal.
I think I'll try the diesel trick too. I'd like to take the oil pan off and get that sludge out so I don't destroy the oil pick up.
Thank you all for the advice.

 

I would be leary of running diesel fuel in your motor. I would not do it mine. I would just change the oil frequently, maybe try a synthetic, or other high quality oil. Change it more frequently. Anything harsh enough to break up all that crud in one shot A) isn't going to be a good lubricant and B) could send a bunch of chunks of crud where you don't wan it like plugging oil passages or into bearings.