This is a long one, i'm going to best describe the few problems with my 96 Ram.

1) Truck is cold, I start her up and let her warm up a bit. Idles fine until it gets to the 130 mark on the cluster. Now she starts to run rough and get a "hissing sound" sound from the intake area...like if she was starving for air. After a awhile the truck straightens itself out....runs fine. Yesterday I ran out got some CRC throttle body cleaner (I only get the good stuff) and the TB was caked. Cleaned the IAC passage area too. I cleaned it while the engine is off and TB on the intake. Cleaned her up good all the way around. Start her up and get it to warm up a bit, runs good but still runs rough after a while of warming up but no "hissing sound". One problem lead to another. Now after she warms up, the idle surges high. Great. Ran the truck around the block and still the same. Check all the vacuum lines twice, no leaks. Check the PCV and its vibrating so I replaced it with an old operating PCV. Still have the same problem. I read my FSM and read that the IAC and the MAP sensor controls the idle. Could have the TB cleaner ruined my MAP sensor?


2) This happened awhile ago. My truck is a 5 spd. This happens when i'm going 15mph and below or vise-versa. The idle surges high until you come to a complete stop then the idle goes down but not at normal idle. I can't use the engine to slow down or it'll just keep right on going. I can't tell you what the rpm's are since the truck didn't come with a tach cluster (Chrysler blooper).


Anybody that can pin-point me in the right direction, i'll appreciate it.

 

running poor after warm up is often the front 02 sensor.

the 2 most important idle sensors are the TPS and IAC. they interact in weird ways and i've given up trying to understand each. when i get an idle problem i just replace one. if that doesn't fix it i replace the other. not very scientific but it gives me less of a headache.

 

There's no way you can properly clean a TB with it still on the truck. Remove it from the intake and remove all the sensors. Throughly clean the IAC port and the tip of the sensor being careful not to push or pull on the tip. With the TB upside down, check the 2 vac ports to make sure they are not clogged up with gunk. The small one is for the MAP sensor and the larger one is for the evap system.

After reinstalling the TB, disconnect the negative battery cable for 1-2 minutes. Reconnect the cable and start the engine. DO NOT rev the engine...just let it idle and come up to operating temp. Shut the engine off, restart it and take it for a drive.

If this doesn't cure your problem, you may have to replace the IAC sensor or the TPS. Good luck.

 

I had some running around to do today, I thought maybe driving around will re-learn but it didn't and finally threw a code, code 25. I took the TB off and took off all the sensors and bracket and stuck it in Gunk Carb. Cleaner. I'll run out to the junkyard and get another IAC motor.

Will post updates.

 

I reinstalled the TB and the sensors as well. I got a factory IAC sensor from a working truck. Cleaned the pintle on the sensor. I took the negative off the battery for about 1-2 mins, let the truck run up to normal operating temp. Idle was good but also hesitated a little. Shut it off and restarted and took a drive. Idle is kind of high, I would say between 700-950 RPM's. I drove the truck about 12 miles and no check engine and stored codes. Re-checked all the VAC lines, everything looks good. I don't know if the PCV is letting too much air in but I ordered a new PCV from Mopar. I'm think the TPS is bad but to my knowledge I don't know how TB Cleaner would ruin it or the idle for that matter.

TB is clean, blew all the passages out. Any other suggestions? I still think I ruined the MAP sensor since it does control some of idle.

 

I don't know what mods that you have done so far, but I would say that your plenum gasket is blown. My truck was making the same noise from the intake manifold, with a blown gasket.

 

Truck is bone stock, it's my work/personal truck. But my truck doesn't make the hissing noise anymore after using TB cleaner.

 

A little update. I think I found the culprit. I think it is the intake gasket but before I start tearing into the engine, I want to see if that what you think. I was coming down a large hill, in 3rd doing 30-35. I noticed that the engine was making this hi-pitch whining noise, like if it was sucking in vacuum. I was driving so I couldn't pin point it. It was the only time that it has done it. What do you think?

About 3 weeks ago, I found that the intake bolts were not torque down to specs. All the bolts except the 2 thats under the alternator and the a/c compressor.

 

Well, as much as I hate to do it..I have to bring this thread alive. So far I have gotten a new TPS sensor and O2 sensors.

Today I figured I would use Mopar Combustion Chamber Cleaner. Did what it said. Tonight I went out and I still get surging at idle. When i'm driving and let go of the clutch, it idle's high again then idles down when at a complete stop. Now, I get this slight hissing noise from the front of the engine.

Now I pin-pointed everything out, vac lines, connections, couple new sensors. I'm thinking it could be my intake manifold gasket thats shot.

What do you think?

 

Get some carb cleaner, start the engine, and shoot some cc at the assorted gasket areas. (vacuum lines wouldn't hurt either.) If at some spot, idle changes, hit it again to verify. There's a leak.

Favorite spots are intake gaskets, and injector o-rings, TB gasket (which I assume you have already replaced.....) and dried/cracked vacuum lines.

Pull the air cleaner off. Crack the throttle wide open (engine off......) and use a flashlight to have a gander down the throttle body. See any oil down there? Time to yank the intake, and redo the plenum gasket. (A known point of failure on these trucks)

What do your plugs wires cap rotor look like?