We own a 1999 Dodge Ram Quad cab with an automatic 5.9L engine. We recently installed a remanufactured 5.9 and it was running fine, aside from a vacuum leak we have not been able to find. Hence, 4 wheel drive is not functioning.
A month or so ago, the truck started dying while sitting at an idle At first, it would start back up right away and be fine for a while.Then it got to where the truck does not want to idle at all while in gear. In neutral, the RPMs will fluctuate up and down for a few seconds, then the truck will die.
When shifted to reverse, the truck will lurch violently and die.
A local shop replaced the distributor and a sensor of some type, including the iac. We have replaced the overdrive solenoid.
All of this has been to no avail. Incidentally, we did discover that the previous owners have changed the transmission from the original 46RE to a 46RH which is out of a B series van.
Any suggestions would be very appreciated.
Thank you in advance

 

Was the old throttle body used? Was the fuel sync set? Iac's can be a hit or miss, Have heard others have gone threw 3-4 before finding one that works. What brand was put in?

 

The mechanic at the shop replaced the distributor and said he set the fuel sync. I believe it was the old throttle body. The plenum, however, we ordered the aluminum gasket kit online. I am not certain of the brand on the iac.
I stand corrected on the new iac theory. My husband told me that the mechanic put a new one on and it made no difference, so he put the old one back on.

 

What codes is the PCM spitting out? (should be a slew of trans codes..... that's expected, any others?)

 

No codes. My husband reset the computer to clear the codes after replacing a part. I believe the truck would need to be able to run in order to decipher any codes. Correct? Before that the only code given was P740 which was the solenoid that he replaced on the trammy.

 

Then you likely still have the 46RE in there. Otherwise, the PCM would be complaining about it..... Easy to check. Just look at the number of wires on the connector going into the trans. (drivers side, about halfway back.) 3 wires is RH, 8 wires is RE.

I think I would start with the basics though. Pull the throttle body, and thoroughly clean it. (especially the IAC well.) Leave the battery disconnected while you do it. When you have it all back together, turn the key to On, count to ten, THEN start the motor. It *should* figure out the idle on its own...... If the idle doesn't start off around 1500 rpm, and then slowly come down, either the IAC is bad, or the PCM is.

 

Thank you, we will try that. Although, it is weird about the transmission. It does indeed have eight wires, but when we ordered the overdrive solenoid for the RE,we received the wrong one.The solenoid we needed was a perfect match to the one for the RH. In fact,I was standing right there when it was reordered from the mechanics shop downtown and they told me it was out of a B series van. Stranger things have happened, I suppose.
When the truck was in the shop, the mechanic said he synced the fuel. If he screwed with the idle set screw afterward, would he need to sync the fuel again?

 

Not sure base idle is even adjustable on these......

 

My husband said he cleaned the throttle body before reusing it with the re manufactured engine. He then assured himself it had indeed been cleaned when the truck was acting up. He also said that the mechanic removed the iac at one point, with the truck running, and it made no difference in the way the truck ran. I do not know if the foregoing is relevant or not.
Where exactly in the engine is the PCM? I seem to find myself left with a truck that will not run and my husband gone away for 77 months lol.

 

I am not sure if it is relevant or not, but when we jacked up the rear wheels and started the truck, if touching the brake it would die when shifted. When not touching the brake, it would idle fine. We were told because of that, it was the overdrive solenoid which we replaced. Not the problem.