I am having the same problem with my '99 Ram. Nobody seems to know how to fix it.

 

Us with out SS/T's and other 2nd gen rams have this problem aswell. I was also reading about carbon build up being a cause aswell. I don't think it's anything too serious. Mine will do this when it's cold. It's a tad over 35* this morning, it'll be interesting.

But just to make sure, does it like "click" and the idle will change? and then it'll "click" again and go to normal and so on? That's what mine does, along with the neighbors jeep who's is a 2000, about the same time our rams were made. It has to me a chrysler thing for the time.

 

With mine there is no clicking. It just seems like it loads up and if I don't rev it a few times it will eventually shut off. Also if I don't allow it to warm up it will run rough for about a 1/4 mile.

 

You might check for a worn/bad/broken vacuum line, probably in/related to the intake system. Also check the IAC. I've had a few people with similar problems when I was working at AutoZone, and when we swapped the IAC and replaced all the old vacuum lines, it seemed to go away.

 

I think I know what it is...I believe the plenum gasket in the intake is bad, as I can hear a vacuum leak pretty loud when it does it...and, its coming from that area.

Also...mine will load up so bad sometimes at red lights that I have to floor it to make it move, and it'll just kinda chug along, then, all of a sudden, nearly flip you back in the bed when it clears up...lol

Also...Alex, no it doesn't click...doesn't idle rough and go back idling smooth....just idles rough.

And, the PO moved my IAC to the intake pipe (going to the fender)...so...could that have something to do with it?

Also...as weird as it may sound...seems like it does it more with the air on...strange yes.

 

Where is the IAC and what does it do? I know that it is not the intake gaskets, I just replaced them a month ago. I will get a can of carb. cleaner tonight and start checking for vacuum leaks.

 

i had this problem on my 98 and it was a back pressure problem, since theres no cat on it the engine does have enough back pressure to idle. put either a stock cat on it or some kind of muffler and it should clear up, you can find a stock replacement cat on summit for about 250 bucks

 

It's not a back pressure problem. My truck does have a cat on it and a muffler and neither are plugged up.

 

hey strange does yours do it all the time or just once in a while

 

just once in a while, for no reason at all. (no one thing starts it)

 

Sorry to revive an old thread.
Did anyone get this issue figured. Ive got it big time on my 98 1500 2wd.
Starts with erratic idle then the hissing starts and I have to keep my foot on the gas. Light turns green and it doesnt want to go and you really have to lay into it. When you do it buck several time and then a couple of loud pops from under the hood and it tries to correct itself and you get thrown back in the seat. This is a safety issue as it can get away from you and hit or hurt someone if you dont catch it.

I havent changed out the TPS or IAC yet. Ive been reading that its probably niether of these. Ive gotten down along side of the intake with a section of rubber hose to my ear and I dont hear anything. When I do get it to do it while parked I can hear it and its directly inside the intake. Ive confirmed this by covering the intake and letting off. You can physically hear it in there.

Im lost

 

hey...just saw your post...

well...I pretty much have it narrowed down to the o2 sensor.

I unplugged one of the o2 sensors and the truck has been running fine for about 3000 miles now...lol
So, I asked a Dodge dealer, they claim that when a sensor is unplugged and the CEL comes on, the computer goes into limp mode...but, I don't believe that one bit.

So...to test this theory, I plugged that o2 sensor back in while the truck was running, almost immediatley it started loading up again.

I then unplugged the other o2 sensor...didn't make a difference. I even drove the truck around the block, everytime I came to a stop it'd load up again.

Got underneath, plugged that one back in and unplugged the o2 I originally had unplugged, and all was well again.

So...now I just need to get under there with a torch and get the old one out. I have a new one I got out of the junkyard (someone had just put a new on in a JY truck and it came right out...haha). But, once I do that, I'll update. Its just getting the drive to do it...haha.

 

i have a 98 1500 slt and it does the same thing at idle and when you excelerate it makes the leaking sound and when you let off it goes away i definately think its something with the intake