Disconnected battery to fix something, now truck stalls....help!

[DenaliAK]

Had to remove my battery to fix a leak in the windshield wiper system. Ever since, my idle has been really low...about 400...and it's totally stalled on me a couple of times during rapid deceleration. Theoretically, nothing should have changed as far as performance goes, and it was running fine two hours earlier when I took the battery out. I'm not sure what to make of this. I ran some Seafoam through it yesterday, but if anything it just made the stalling worse.

Interestingly, my electronic rear-view mirrors that hadn't worked in probably 6 months suddenly work just fine. Apparently a power reset can do wonders. Glad I didn't invest in new motors or labor on that one.

 

[OmarR]

Since you disconnected the battery, there are parameters that the PCM is learning again. Sometimes it's slow and unstable, and if you ever get a Blackbear tune, there is a software update that is given with the tune.

I have had this happen before. I disconnect the battery again, reconnect, and go for a decent drive to re-learn again. Make sure your battery is healthy too.

 

[DenaliAK]

Since you disconnected the battery, there are parameters that the PCM is learning again. Sometimes it's slow and unstable, and if you ever get a Blackbear tune, there is a software update that is given with the tune.

I have had this happen before. I disconnect the battery again, reconnect, and go for a decent drive to re-learn again. Make sure your battery is healthy too.

I thought about the computer just relearning things again, since that's how my other car works, too, but to just flat out die while moving around a corner isn't acceptable when my wife is driving with kids in the car. I'll try disconnecting then going for a nice long drive and see if it helps.

 

[bkboatnsleds]

Agree - this does not sound like a learning curve to me. Perhaps its just a fluke - and something else is going? Fuel pump? Is there enough fuel in tank?

 

[DenaliAK]

Fuel level was not an issue.

I disconnected the battery, then reconnected it again. Filled up the tank. Took my wife to dinner in a town down the highway about 35 miles. Came back. Average speed was about 60, very little traffic, no wind at all which is unusual for this highway. Got exactly 18mpg according to the truck computer.

Still has a low idle that surges between 3-500 when you come to a stop. It didn't stall on me, but is very close at times and I think it will under the right circumstances. So, I don't think the PCM reset is the issue.

I'm taking it to the shop that repaired the wipers, since it didn't do any of this before I brought it there and did as soon as they finished. They were the ones that noticed, actually, and they asked me about how it normally idles. We'll see what they come up with.

 

[bkboatnsleds]

Very weird.

 

[91RS]

What year is your truck? If it is a 2000-2003 you're going to get a PCM software update for the low idle and you also need to clean the throttle body to completely fix it. Make sure to clean the throttle body first before the PCM update so it doesn't start learning the dirty throttle body.

 

[DenaliAK]

It's an '03. Previous owners were pretty meticulous about maintenance, unless the update was in the last 3 or 4 years. I'll call the dealer and see. If it's a manufacturer update to fix an issue, they can't charge me for it....but they will most likely try.

*Just called the dealer, and the previous owner didn't get any updates that they see, but it wasn't in the state all that long before we bought it. They did get a new fuel pump in '07 though, so I would think that wouldn't be the issue. The guy said a common issue is intake gaskets? I don't know what those are....

 

[91RS]

It isn't a recall so you'll have to pay for it.

 

[bkboatnsleds]

Intake gaskets are common on this motor.. I would think if they were that bad that it would have thrown a check engine light with a lean code by now. When its idling rough you could try spraying some brake cleaner by the intake gaskets to see if you can't hear the rpm's rise. Kind of a hard test - but may be worth a shot.