HI All about 18 months ago I posted because of a problem I was having with a rough idle & electrical surges and still having problem. ok let me back up to when it started my keyless remote was setting the alarm on and off to frequently even with key in ignition, most likely a weak battery in the remote, switched the remote & key have 2 seemed better than a week later from a cold start doors opened as it's supposed too, but when I put the key in ignition radio, air lights went on but not the engine (dead silent) OK so I figured it was the kill switch but couldn't find it, called a few people (dealer, mechanics) no one would help so I had to call an auto locksmith, he replaced the lead wire (Ignition switch Cable) said was not a biggie happens with time and the security system is behaving normal since.

BUT since then I seem to have some kind of a drain on the battery causing a rough idle only when I'm in drive with my foot on the break. Getting voltage surges from 12-14 and she starts grumbling and feels like she want's to exhilarate, also my fuel usage has has increased dramatically. Took her to the dealer ran a full diagnostics - everything running normal but might be the alternator starting to go? Took her to 3 mechanics - no one could find a problem. Finally 6 mo ago in a terrible rain storm after parking she started to chock, rumble, fart coughed and shut down and wouldn't start. Called AAA and bedded me home, said I had water in the engine not a biggie, let it sit for a day or 2 if she starts up normal just change the oil. She did on my way to change the oil she started grumbling again and hesitating.

The mechanic said 1st it was the battery, changed it, than he said it was the alternator, replaced it. Asked him to check the wires, leads etc. said everything was normal. OK so now for 18 months I'm still having the same rough Idle & electrical surge problem. Yesterday she was giving me problems on start up & SYS was flashing. Took her back to the mechanic who changed the alt & battery. Says the battery is bad? 6 months old? he's changing it today but said there is some kind of drain. Stopped by an car alarm place on my way home. Said the guy who changed the Ignition Switch Cable should never have changed it and now there might be a ground, short, incorrect cable etc. etc. And to bring it in and let his mechanic look at it? duhhhh. I'm really getting tired of people charging and finding nothing wrong. Hit and miss let's try this or that. Whats going on with my baby? she was fine up to that day, is it the cable causing this problem.

 

find a better mechanic?

 

I would if I could

 

What is the voltage at idle?
What is the voltage when running poorly?
What is the voltage when cruising down the road?

 

Hard to tell right now as battery is bad, cold start 14.9, running 14.1-3. But battery is bad as of the last indecent The Battery that was ordered for today turned out to be miss marked So he couldn't but it in.

But before I would say cold start higher 14 after driving around a bit around 13ish and in Neutral & park the same after warm up but at a stop
jumps between 14-11.7 until I start driving Does that help?

 

Well, they changed the battery, the good new is it isn't grumbling as much at a stop, but the bad news is I think there is still a drain OK so I leave the garage it's reading 14.1 and stays there the trip home approx 5 miles. Next morning start up was fine volt gauge is reading 14.7 from a cold start and slooooowly decrease to 14.1-3 and stays in that range the rest of my driving. only fluctuated to 13.9 when I put the window down and right back up to 14.1 and holding there????

Shouldn't it start in the 13 range??? is there still a drain from somewhere. New alternator when I changed the battery 6 months ago. what else could be causing this problem.

 

Wish you were near me.I would like to find out the problem.I like these challenging electrical problems.Sounds like your car is misfiring as well as has a battery drain issue.Bring the car to a shop that specializes in electrical problems.Might have a disconnected wire somewhere.Keep us updated on what you do & find

 

You can locate a battery drain by disconnecting the battery ground cable and connecting an ammeter from the positive terminal to a good ground, e.g. the disconnected ground cable. With no courtesy lights, underhood lights, etc. on, there should be almost no current flow. If there is any significant current, pull fuses one at a time until the flow stops. This is the circuit that is drawing power. Remember, the interior and underhood lights have to be off.