Rough, low idle after removing battery

Just so everybody knows, and doesn't freak out like I did yesterday...

After resetting my battery terminals yesterday while wiring some switches, I turned my truck on and it immediately stalled and died. Started and ran the second time, but did not idle high like it usually does when cold. It was at 500rpm in park, and about 450-400rpm in drive/reverse. The truck was shaking pretty bad, and I got scared thinking I pulled a vacuum line out by accident. Seemed to drive ok, just idled weird.

After about 15 minutes of driving and restarting the truck, it was running fine again. So if this happens to you, don't panic!

 

x2, mine does this every time I disconnect the battery for more than a few seconds.

 

Takes a while for your A/C to start working again too.

 

I assume someone will chime in if I am completely wrong. I believe when you disconnect your battery you also reset your computer for all your fuel and air mapping back to factory. You then have to rebuild the program by satisfying a variety of driving conditions like a 0 - 60mph acceleration, cursing at 60mph for X amount of time, and so on. Once you satisfy all the checks the truck should be back to normal.

 

Yes I believe that's exactly what happens...

...and driving in SoCal, I've had my fair share of cursing at 60mph for x amount of time

 

The ECM has to learn again. no worries.

 

I use a 9-volt battery wired to a battery terminal and wires with clips long enough to hook to both the positive and negative battery cables. It keeps enough current in the system to retain the radio pre-sets and helps with the computer re-boot as well.

Ray

 

Interesting...

and hey nice avatar! Do you have a Cobra? I just sold mine a few months ago

 

Yep. That's our car.

Ray

 

X2 again lol. Houston traffic sucks around the clock.

 

Hey, I just did the same.. Now my trac off, check engine lights are on.. Had black emissions and it drives at 20-30mph... When I first turned on the truck it had a rough idle then died.. Second time it was rough but stayed running.. Battery had been completely depleted and when we tried to jump the battery.. My "help" had their connection backwards.. The black emissions.. The slow driving.. And the trac off light are freaking me out.. It is due for a tune up doh

 

Woah, so they applied positive to the negative and negative to the positive? Sounds like it may have blown a few fuses that control stuff.

I'd be careful driving it. Sounds like it's in limp mode.

 

Yeah they sure did.. My baby IS limping.. Smell something electrical too.. Checked and replaced all fuses that I can get to without taking apart the fuse box.. I did change the alt fuse.. All other fuses are replaced an good.. Starter? Could it be the alternator? It stays at 2000 RPM.. Have to let off the gas a lil for it to gear up.. But in all the fastest it'll go is 45mph.. Everything else is working lights, stereo.. Windows doors.. It's the drive, that's off :/

 

Weird. Never h are if this before. Nor have I ever noticed it on my taco before.

 

Took my Tacoma into the dealership. Had some codes reset.. The O2? Now it's back to normal.. Although I do need a new airflow sensor.. Started and alternator are good.. But yeah.. Moral of my story.. Hook up jumper cables your dammnnn self

 

Cleaned battery terminals and the same thing happened...>500rmp idle and some heavy shaking, but never stalled out. Drove fine except when I was stopped on a hill and let off the brake. I rolled backwards about 2 feet before it kicked into drive...almost rolled into the car behind me! Drove around for 15 mins or so, on and off the freeway, and when I pulled in to my garage the idle slowly adjusted back to normal. Hopefully tomorrow she starts up with no problems! Not a pleasant experience, I'll think twice before disconnecting the terminals again.

 

That is not normal. It should have already been in drive.

You might want to check the transmission fluid level.

 

Hey guys, I am also having this issue, however I drove it for about 10-15 mins and its still extremely rough foor idle, I just replaced the alt and the bat today (junkyard alt, fresh bat) its charging at 14.2 just wondering if anyone has some good news for me i idle at like 150-250 RPM.... really stressful and starting to lose some hair over it.

 

That's is a really low idle. Also supposed to be charging at 13.8. You sure you put the belt on correctly?

 

yeah I know its on properly 100% I was told by a few friends that its ok for it to be around there it hits 14.2 and dips to around 13.8 fluctuates. and i know the idle is really rough its scarry AF im worried about my poor little truck