Don't know what to look at next, literally can't drive truck after situation has downgraded. storyline, patience required:

got an 03 1500 5.7 hemi. had it since day one, awesome truck. had some free time last week and decided, because it's urged so often here, that I should pull the throttle body and clean it up. was super meticulous, taped off connectors as they were disconnected, used brake part cleaner, etc. body was fairly carboned up, so as I shinied it up, was hoping for good things (you know, rocket launch starts, 18-19 mpg...). everything went back together fine, and I would have eaten off the thing.

started truck right up, took for a neighborhood spin, seemed OK, but not impressively different. if I hadn't done the procedure, I wouldn't have noticed anything significantly different. decided at that point that a "soft reset" of pcm would be a good idea. pulled the pcm fuse, did the key to on trick, ding, ding.... then the downhill slide started. first thing I noted was that when I moved to the key to start position, no immediate response from starter - there was (is) a definite lag from key to start position and any response from vehicle. still starts right up when it kicks, just a noticeable lag from key to activity. then, I noticed that rpms were up and down - probably 700 to 1000 range, whether in gear or in P / N. went on another neighborhood run, several in fact, and that never really changed. rpm's fluctuating, a little surging to go with that at stop lights, etc. not great, but I could drive, and stop, and the stereo's loud.

but, figured a full, pull the negative cable, completely kill the memory and reset pcm might be in order. so, went to pull the negative cable off terminal, and the hole post came out of the battery. it was the original battery, which I had never had to touch previously, but I've still never seen that happen before. needless to say, my system got a good reset because I had to pull out the battery and drop some change on new shiny one. I thought to myself that maybe the battery post was an instigator, and the new battery and full pcm reset would give me wings and set me free.

hooked up new battery, greased up terminals, made sure to do the key on hold for 10 seconds deal and everything seemed cool at that point. put the key to off, took a deep breath, key to start, same lag before fire up, at start up the rpm's are now crazy - 500 to 1500 for several cycles until it hits 500 and just dies. I can rev with the pedal, but it won't really hold at a steady spot. last night I pulled the throttle body again and went back thru the whole arrangement to make sure nothing was put back wrong. double checked it all, all looks good. re-hooked battery, key to on for throttle reset..... crazy rpm surges and dies after a few cycles.

I don't know where to go next: ignition itself? some kind of ground problem? simple as an alternator? throw out pcm? ideas????

 

My sisters 99 Ram did this sort of thing after the battery died.
It wasn't dead for long, but aparently long enough to throw the PCM off for some reason.
Truck would not hold an idle for ****. She drove it home doing to fun old foot brake gas stand thing with me and my dad behind her. About half-way home (5 minute drive) the truck started behaving properly again.


I'm wondering if you may have the same problem.
Another thing I would check is the IAC motor on the TB, your supposed to either clean them or replace them and I'm wondering if maybe when you were cleaning it, it broke. (Its not uncommon)

Happy hunting (lol) and Welcome to DF!
Hope you get your problem sorted out, someone else should be here soon to help.

 

Your delay with the ignition is normal. You just seem to have noticed it through your troubles. Mine does it too. There's a good full second delay before start-up. it's been posted before and discussed. It's normal.

First, make sure ll of the tubes that connect to the intake tubing are connected. A hose that has fallen off will create a vacuum leak and cause your idling issue's.
Then
As far as your reset. Turn your ignition key to the on but not started position and depress your gas pedal and slowly release. Do this twice and then start your truck. In most instances you shouldn't need to calibrate your throttlebody as it should do it itself, but try it as it can't hurt. You can also turn the heat on full blast for 30seconds and wait for the idle to settle.
As to the above. There is NO IAC valve on the Hemi T/B.
Also, you aren't suppose to use Brake cleaner on a sensitive part such as a throttle body either. You should have used throttlebody cleaner instead.

 

Just a guess, but it sounds like a intake leak problem. Maybe when you took the TB off you tore the gasket, or maybe when you put it on, it's not quite set on right. Since you can't hardly idle, a normal leak test is useless. Go back to the basics, and just pull the TB again. Inspect it, and make sure your gasket is still good.

 

Dodge has issued a TSB saying DO NOT use throttle body or carburetor cleaner - brake cleaner ONLY!

 

Vaccum gauge is your friend in this case. Check for leaks associated with components you removed.

Interested to hear what you find.

 

Really? They say to use Brake cleaner rather than a milder chemical?
Can you please post up a link to this TSB. Thanks

 

There is a cause and effect and I wouldn't start throwing parts at it because it's probably something to do with the throttle body cleaning. did you unplug any wires and perhaps crack a connector? It sounds like a leak but with all the electrical issues I would back track again. All of that going on and no check engine light? There must be some codes to work with.

 

your truck was adapted to idle through the dirty throttle body, you can reset it if you want but it just needs time to relearn and adjust to the new flow and correct its idle

 

here's the update. pulled everything down to intake manifold again. worked it all back on, like a scientist in a dangerous chemicals experiment.

crazy idle again on initial restart, but it seemed to quickly learn to behave, and settled in a little. took it for the neighborhood spin, and was actually fairly pleased by the time I got back to my barn.

the last time I took my foot off the gas and let it coast / idle, etc light flashed, CEL came on, went to limp. same as many others have written, once I parked and shut down, upon restart no etc light, but CEL stays on. I can drive around, but at some point, usually if I'm headed downhill, and take foot off gas, same thing: etc light flashes, goes to limp, .... shut down, restart, drive away...

codes I got are 2118, 2110, 2106.

new ideas??