MY 1996 ram 318 automatic with 137,XXX miles did the same thing as yours. SAME thing. I did the Hughes fix, changed the TPS, IAC, MAF, plugs, wires, both 02 sensors, all of that, no change, still the same sorry surging, stalling POS. then bit the bullet and got a new CPU, runs like the day I picked her up from the showroom. not saying this is your issue but Don't over look it. My truck was heading to the junk yard. I was tired of it then decided to change to computer and she runs like new.

 

i cleaned my iac again today and the bore it goes into.started the truck and it revs up to 2000 rpm then idles down to 1100 rpm.after a minute it starts surging from about 1100 to 1300 rpm and i notice the fan is kicking in and out.is this normal?i might have the common plenum gasket leak but with 59000 miles on the clock i have to rule out the simple stuff first.i cant help but think my trans acting wierd and the tranny shifting problems and the surging idle arent related somehow....thanks for the responses.

 

Cleaning the IAC is NOT a solution if it's bad. And how do you notice the fan "kicking in and out"? Do you have an electric fan?

 

i have a normal fan with the thermal clutch.

 

Like I said, cleaning the IAC is not the end all solution to your problem, and the IAC might not be the prob at all. But chances are good it's bad(common prob). That said, add ALL the info about your truck to your sig. Make's diagnosing probs easier.

 

i will change the iac.i dont know if i mentioned the idle doesnt surge while in gear.

 

changed the iac today.upon first start it idled the same high and surging.i have restarted the truck and drove it and it idles a little different each time.upon last start it idled a constant say 1250 rpm with no surging.at one start it idled at 1000 rpm with no surging.the other times it was as it was at the start say 1100 to 1250 rpm....what gives?

 

damn. that's worked for me both times.

as far as i know, the idle is controlled by some mysterious balance between TPS and IAC. when TPS drops to idle, then IAC takes over, under pcm control to move the pintle in/out to maintain the target idle speed.

did you reset the pcm after changing tps and iac? if not try that.

sorry, i'm out of ideas.

 

if you mean unhooking the neg side of battery and turning the key,i did this with every change.

 

talked with a certified chrysler tech tonight by chance.i will let you know what i find and how it turns out.