Have a 1996 ram 1500 5.9l and am having idle issues. Idle will drop when at a light, stop signs, or when sitting at idle. When the idle drops, there is a loud sucking sound at the throttle body. Sometimes the idle will kick back up other times it will die. Also have some issues with loss of power while driving. Have replaced throttle body, plenum gasket, intake gasket, throttle body gasket, map sensor, IAC, throttle position sensor, all fuel injectors, distributor, plugs and wires, timing chain, head gaskets, heads, header pipes,header gaskets, transmission rebuilt with a tow package and shift kit, fly wheel and torque converter replaced, new alternator and battery, and the ignition coil. There is a crack in the air box, not sure if this could be causing the problem? All of the sensors have been replaced numerous times. This is getting very frustrating as we believe that the problem is a simple fix, but nobody can figure out what the problem is? Many of our friends, my husband included, are mechanics (some backyard and some schooled), and nobody can figure out the problem. Please help!

 

Welcome to DF. Sounds like clogged cat and bad o2 sensor. I'll move your post to the 2nd gen ram section. The new member section is just for intro purposes.

 

^ holy cow. that's everything.

the sucking sound is the normal sound of the IAC opening up more to try and maintain idle.

do this - rent a compression tester from your local parts store and do a compression test. write down the numbers and report back.

 

You could reset your PCM. Worth a try.

Sounds like you have a bad IAC

 

Except for cat and o2, (unless of course it's just not listed) plus it's stated that there is a power loss.

 

IAC just replaced for the third time yesterday.

 

replacing O2 sensor today, and have not cat due to header pipes. How to reset PCM? I read to unhook negative battery cable, turn key to start position for 30 seconds then reconnect the cable. did this this morning and it did not work. is there another way to reset? We also ordered new positive and negative battery cables, and crankshaft position sensor, which will be in tomorrow. I will have to tell my husband about renting the compression tester and see if we can figure something out.

 

Remove the negative cable BEFORE replacing any sensor. While you do the work the PCM will be reset by the time your done. And what brand parts are you getting? What brand is the IAC for instance? And what brand are you getting crank sensor? And was the distributor replaced or just the cap and rotor?

 

iac - replace once, maybe twice if it acts different but still bad. after that move on to something else. the TPS has a interaction with idle, but since you've replaced it already, it rules it out.

the only sensors you haven't replaced yet are crank position and cam position. both are a little hard to reach and you're not experiencing stalling/no start, so there's no obvious reason to change them.

i didn't see PCV valve replacement? that's an easy and cheap one, and if bad, can cause a real bad vac leak.

has anyone with an expensive scanner done any checking yet?

 

Also, double check ALL your grounds