TPS in theory could cause it due to the computer thinking you're at a lighter throttle and delivering less fuel. You need to make yourself a checklist based on all the advice on this thread and go through each one until you've found or solved the problem.

 

ok.. will do .. when i figure it all out I will post.. thanks

 

well.. after last night and it running fine at idle in drive and park... I started it up this afternoon.. idled fine for awhile.. then started acting up again.. not as bad as before, but in drive it surges up and down a few rpms.. and sputters slightly when i take off.. still has the sputter and bog when i floor it driving but will eventually clear out (backfiring through exhaust) .. so it's not in the loop of when the engine is cold, but somewhere after the engine warms up. Ive been looking everywhere on the internet but it seems most have this problem when it's cold.. not when it warms up..
Also.. i did notice off the egr valve on the back manifold there is a vacuum line that goes to a plastic piece (with wires to it) and a cple vacuum lines coming off it.. ONE of the vacuum lines coming off the plastic piece is broken and i can't see where it would go..it comes off a 90 and it's a small hard piece of plastic .. i don't notice any suction from it when revving the engine.. but not sure what it is.
I sitll have to do the 02 sensor and check the CAT ..but if i slowly start giving it gas on the highway it will get up and go fine way past 3000 rpm and keep pulling until it's floored... then it sputters...
driving on the highway it drives fine, as long as i don't flat out floor it.. it will go fine.. and it stops and idles better, but still has a small surge but nothing like it was before i redid the wires and played with the distributor last night
I will also have to look at the cam sensor in the distributor and see if it's lined up correctly, maybe clean it also.
on another not.. the dang gas gauge wants to float around now.. i had 3/4 of a tank and then it was 1/2 then down to 1/4,.. seems to jump up and down slightly when the idle runs rough.. i have to turn it off.. turn key back on.. let it sit and wait for gauge to come back up to (presumably) normal range

 

ok, so after going over plenum failure threads.. 02 sensors and TPS threads.. so far, my truck has not had the symptoms that are frequently related to those. NOT saying the plenum gasket has been fixed or not..(don't know 197,000 on truck)

I have power, it drives great on the highway, it will get up and go on highway, doesn't surge when driving it unless sitting at idle in park between 400-600 rpm and same for drive. JUST sounds like it has a cam and the idle needs to be adjusted higher..
Once I take off it clears out and drives fine until the next time I stop. AND only when WARM... cold it drives fine.

 

02 sensor, especially the upstream will affect driveability when warm...sputtering etc..replace with denso or ntk, no bosch. Didn't read all way back, but TPS when bad will give short 200 rpm surges. Normal idle would be 600/650, when warm, 800 to1000 when cold.

 

Check your wiring harness. Make sure it's working right. Not saying its what's wrong biting did it along with misfires. My harness was jacked. Learn it step by step and learn ur dodge its worth it. They are great trucks and u can grow with them

 

have you cleaned or replaced the IACV?

 

I agree with ReadRam. O2 sensor, and the reason it's bad (not only from age) but I will bet the plenum is shot,and or the pcv is sucking in oil. The first thing to check and replace on a magnum is the plenum,cat and o2(s).

 

yeah, have to check the plenum... as of now.. everything works good.. i can get on it on the highway and mostly floor it, but at full open it pulls but sputters out the exhaust, if I let up just a hair on the gas it goes perfect..
still has the slight rough idle and will clear in a few seconds of taking off in drive.. drives fine on highway..
the main problem is the slight rough idle like it's flooding itself in drive (AFTER warming up) and the FULL throttle sputtering ..

once i get some time and $$ i will pull the 02, check the CAT and look at the plenum, clean TB... then repost to see if all that worked... LOL.. dreading the plenum...

 

okay, update: I hurt my back about a week after this thread... so no working on truck for a while. Today though, after the truck seemed to be getting worse. I put in a new IAC and went to put in a new 02 sensor. The old 02 sensor was stripped (like someone had tried to get it out before). I sprayed it with WD-40, let sit, heated it with a torch, used a pipe wrench, breaker bar.. nothing.. would not come out. So just to see what would happen i hooked the new 02 sensor into the harness and wired it up out of the way under the truck (left the cap on the end of it). The truck now idles great and doesn't die or anything in drive and drives good on the highway.
Leaving me with this one other symptom. I can't get this thing to go over 3000rpm without sputtering and surging at a full open throttle.. if i back off the gas a bit it will go but still surge and pop out the exhaust... ?? in park, if i feather the gas it will go over 4000 rpm with no problem, but if i just floor the throttle it hits 3000 rpm and starts popping and won't move from there.. I also noticed the down pipe where it connects via 2 bolts to the exhaust is broken and leaks there.. would a new exhaust and converter help you think ??