I have a new to me 1996 Dodge Ram 1500 LT V6 3.9L Magnum truck with Automatic transmission and only 77,790 miles. Carfax report was clean and it has had regular service including a new serpentine belt at 60k, along with a transmission flush and new pan gasket.
It ran great for 100 miles then developed the intermittent won't idle, won't start problem so after reading other posts, I decided to clean or replace the IAC module and remove and clean the throttle body.

I removed the air filter housing and the IAC module/valve was a new looking Holley brand part. I unhooked both posts on the battery, pulled the cable and it was clean. I pulled the spline bolts and the sensor looked brand new. The throttle body looked brand new, clean as a whistle and was also a Holley brand. Even the gasket looked brand new. I replaced the air filter and put everything back in place and truck started and idled fine. It ran fine for 15 miles, then wouldn't idle. The next day it idled fine and drove 8 miles and died. Would turn over and try to start but wouldn't ever run. I got a ride home,waited a few hours, went back and truck started but wouldn't idle. Drove with one foot on gas and one on the brake and gearing the automatic transmission down to avoid stalling.

One mile from home, truck stalled and died. Turned over, would sputter but never start. I pushed it out of the road, walked home, waited an hour and went back with tools and starting fluid etc. Before popping the hood I tried starting the truck and it started. I didn't wait to check idle, but drove home without letting it idle, and once safely home, it wouldn't idle and died. It would restart but would die when I tried to let it idle. Waited overnight, and truck starts and idles fine.
I've never got a CEL since owning this vehicle and previous owner says its always ran great.(What else would he say?)
Are Holley parts normal?
Should I replace a new looking Holley IAC valve/module?
Any ideas of what else this might be?
I'm afraid to drive to the dealership or parts store after stalling and not being able to restart on busy single lane shoulder less roads with lots of 4 way stops!
Thanks if you read this far, and if anyone can make any suggestions, I will appreciate it. I can also try to get correct terms . Sorry folks, I'm a weekend mechanic who just had back surgery and barely made that mile walk.lol

 

If you step on the gas a bit, will it start? (when it is acting up.)

Holley throttle body is stock. Don't think the IAC is though. One would think that was at least a reasonable quality part.... but, ya just never know. If the truck will start with just a little bit of gas when it is acting up, you could try replacing it again, and see what happens.... Think I would disconnect the battery, check/clean the pins on the connector at the PCM, hook everything back up, turn the key to On, (not start), count to 10, THEN start the truck, and let it re-learn idle. See if that doesn't help.

If it still does odd and strange things, test the TPS. (really need an analog meter to do it properly, doesn't have to be expensive one.) See what that turns up.

 

Thanks HeyYou
If I step on the gas when it is in its won't start mode, it doesn't help. I tried a little fuel pedal pressure, a lot, tapping, middle, no fuel pedal pressure. I was blocking a major intersection with a policeman breathing down my neck. LOL. I looked like a tap dancer the first stall and no start.
I didn't replace the IAC today or clean the throttle body because they looked brand new. They had the fresh out of the box look. No dust or grime like surrounding engine components. Once, when it was starting but not idling, I pulled the throttle plate on the passenger side of the throttle body back and let it go. It may be a coincidence, but the truck started and idled fine for about 10 miles before truck died and wouldn't start again. It has always started and idled fibe when its cold, unless that's a coincidence as well. I've only had this vehicle for a few days.
I will try to relearn idle as you suggest. And clean the PCM. Thanks for the suggestions so quickly.
Any other ideas are greatly appreciated. I am afraid to get the truck out of my driveway as its 175 yards long and exiting is very steep downhill, so getting it back up might prove tricky.
I'm open to ideas.
Thanks for any help.

 

<p>Is the PCM the black box on the drivers side firewall</p>
<p>I'm pretty proficient with cleaning connectors but very new to Dodge Rams????</p>

 

Box behind the battery on drivers side is Power distribution center. PCM is mounted to the firewall, on the passenger side. LOTS of wires going to it.

You may have more than one problem. Next time it doesn't want to start, need to find out what's missing, fuel, or spark.

 

[QUOTE=HeyYou;3166189]Box behind the battery on drivers side is Power distribution center. PCM is mounted to the firewall, on the passenger side. LOTS of wires going to it.

Sorry sir. I meant to say passengers side.
I cleaned the PCM connectors with contact cleaner after unhooking both posts of the battery.
I also did the relearn part with the key to "On" position for a long 10 count.
The truck started and idled fine. I hate to get it on the road, but I guess I'll wait for a slow traffic time and stick to a neighborhood street close to home.lol
Can I buy a code tester for use with just this truck?
Are they expensive?
I have been to my local Dodge service center with a company van I used to drive. They slowly replaced part after part on the van when it wouldn't cold start, until they had a $1000 worth of work done. I can't go down that road again.
I hope to make this a weekend project to get running properly first, then to tackle a myriad of lighting and cosmetic issues.
Thanks for any and all suggestions at this point.

 

Also, is there a preferred manufacturer for the IAC module?

 

Don't think the iac is your problem. But preferred would be dealer part around 115 last time i got one.

 

Thanks for your reply ReadRam
I will contact my local Mopar dealer for pricing.
I would really like to hear your advice on troubleshooting my issues before I replace expensive components.
I thank you and anyone else in advance for any suggestions for resolving my issues.
Regard,
Torx

 

OBDII code readers are pretty generic. There are a LOT of options available, from bluethooth adapters with an app for your phone, to the little hand-held code readers (around 250 bucks from auto parts store) to software (free) with a cable (50 bucks) on your laptop, to picking up a "real" scanner from ebay for anywhere from dirt cheap, to hideously expensive.

Most parts stores will also read codes for for free. (the advance auto here just lets me borrow the reader, and use it out in their parking lot. but, I have been a customer there since they opened. )