I recently bought a 01 dodge ram1500 4x4 with the 5.2. Its has 205,000 miles. When i bought it the transfer case housing was busted so i couldn't drive it until i replaced that. The guy i bought it from said it has rebuilt heads on it both sides because he overheated the motor and cracked the old one.new radiator new exhaust front to back with new cat conv. It is a cali truck. not sure if he did the intake pan when he did the heads waiting on him to get back to me but looks clean in the tb. Now that its up and running i notice after it warms up and is in drive but stopped it idles rough but once you give it gas it goes away. does not backfire just kinda jumps if you just let off the brake. I keep getting p0304 code. I have rerouted the wires and checked the spark. I have unplugged the fuel injector wire for number 4 and it really runs bad so its not always missing. i pulled the plugs and noticed the number 4 on the passenger is discolored compared to the rest. and am not sure what that means if anything. maybe someone here knows?
top of pic to bottom is 8 6 4 2



here is plug 4 and 2




I have tried searching for other post and asking friends but havent gotten any answers. also pulled the plugs out of my 99 with a 5.2 and its the same way #4 plug looks the same as the one on this truck but i am not getting any miss fire codes on my 99. so maybe its just a dodge thing?

The truck also has this on the motor. i have no clue when it comes to spacers and stuff like that so didn't know if this might be part of the problem




also looks like they put the old injectors back on it as they numbered them not sure if that could be the problem a bad injector. not sure if they are original ones or not.




I am also getting the mas leak detected on the evap system but have traced all the lines for it and pulled the canister off the frame and checked that and no cracks anywhere then noticed this.


i cant get the cap to screw all the way down. even took the one of my 99 and it does the same thing on the 01. but the one that was on the 01 will screw all the way down on the 99 so it cant be the cap.

here is the neck i dont notice anything wrong with it but i would think this is where i am getting the code from. Can you just replace that?




sorry for the long post just trying to give all the info i had.

 

My experience is the gas cap will return a P0455 code. But that cap is not sealing.

Also, the TB spacer is of no value.

 

Should i remove the spacer then? Its makes it a pain to get the air filter off.

 

The spacer is best used as a paperweight

 

did you check the spark on it id check the plug wire and distributor cap looks like its not getting enough power a little light tan almost white smoke is healthy but that dark usually means weak spark

 

i ran some fuel injector cleaner through the system and haven't got the miss fire code to come back on so i guess i need to replace the injectors. as for the fuel cap it was the wrong cap on it. ordered new one and that fixed the mass air leak in the evap. 99 and 01 gas caps dont interchange.

 

I just finished reahabbing the evap system on step-son's ford last week. Became a near expert on that crap out of necessity.

I don't know that I would jump out and replace injectors yet. Check rotor and cap. Swap injector on that cylinder with another and see if problem moves.