This is my first post here been searching this forum up and down and got some good tips but still havent fixed this truck and i am at a loss on what to do next.

Truck has a misfire on cylinder 4 atleast that is what scanner keeps saying. Very rough idle cant believe it is only one cylinder misfiring but at higher rpms engine light blinks which i gather indicates multiple misfire.

Changed plugs, wires, cap, rotor, plenum gasket and intake gaskets, checked and cleaned injectors.

Truck once warmed up will barely idle have to keep it running when coming to stop. Not using excessive amount of oil or water for 102k miles

Any help would be appreciated i am at my wits end love my dodge but never owned one this new so dont know where to go now.

Thx

 

when you say the "engine" light blinks do you mean the check engine light or the "engine" light? If the check engine light blinks than your cat is most likely shot, and because of that your O2 atleast at the cat is also shot. See if you hear the cat rattling with the truck running, or with the engine cold, tap the cat with a hammer and if you hear something rattling than its shot. Just went through this on my truck as well.

 

the little light that looks like a motor

i had the positive battery wire disconnected overnight before i did the plenum gasket change. the light went out after leaving it off overnight and stayed off for about ten miles all the while is was still missing. The light started blinking around 4k rpm then after a few times of doin that it stayed on and keeps telling me cylinder 4 misfire.

 

MAF sensor?

 

Did you let it warm up first? Or turn the key and go? Did it stumble? Hesitate? feel/sound like it was backfiring? Did you change the o2 Sensor when you did the plenum?

 

yeah i have done both let it warm up take off cold no difference other than when it does warm up the truck wont idle at all. No i did not change the o2 sensor but i am goin to have the cat checked tomorrow and change the sensor as well. Did not think it was cat since i could rev the motor with no backfire thru carb and not much loss of power at higher rpms with the motor warm.

 

should i have the comp reset after changing the plenum gasket??

 

the computer will reset anytime the battery is disconnected for more than a couple of hours. you can tell that happened because your CEL went out. you can force a reset by disconnecting neg batt cable and turn on headlights or ignition to start for 10 sec. this drains capacitor memory.

if you haven't yet done so, you need to do a compression check and write down the results. you may have something serious and unspeakable.

 

There is no MAF sensor on these trucks, just MAP. Doubt thats the issue.

There is no carb. That carb looking thing is the throttle body.

This probably won't solve the issue, and supposedly 2001s are unaffected by this TSB, but it wouldn't hurt, and its free...
http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

Also, +1 for compression check on the cylinders, and let us know the results.

 

the engine light will only flash if the misfire is hard enough to damage the cat. doesnt mean your cat is destroyed.
id swap the #4 fuel injector over to a different port and see if the misfire moves there.
if it does, you know that fuel injector is bad, if not...
pull the manifold and check for a crack at that port. do a compression test on cy #4 and make sure it is in spec.

ive also seen motors miss on one cylinder and it be just a build up of carbon on the valves. so do a combustion chamber cleaning as well. (mopar cleaner, not this other junk)