gear heads unite

2002 chevy trailblazer.... changed battery cause it died.... now car idles really rough (300 to 900 to 300 to 900 rpm's and eventually dies with AC/Heater on... turn AC/Heater off and runs smooth...

any thoughts as to what made it start doing this during a battery change........?

Did you put in the right size battery. Sounds like you are starving the system for energy. Could possibly be your alternator going out. Now that I think about it I would put it in the 80% liklihood that it is going out. That sounds a lot like what mine was doing this summer before it went. Would also explain why the last battery died. Do you have a voltmeter??

i vote alternator but i would ask greg

i replaced it with the same battery.... i'll check the volts tomm at work... it runs fine without the ac/heater on...

new alternator does not insure GOOD alternator but it could be a short in the ac/heater

well i'll remember that if i change the alternator....

i just wonder if i jacked something putting on the new batt... cause when i was putting the neg cable on it sparked quite a bit

Quick checks for a bad Battery or alternator. Kirb, if you don't have a multimeter, just stop by. I can check it for ya.

The quick version... When the car is off, the voltages s/b 12 volts. With the car running, between 13-14 volts is norm.

https://www.youtube.com/watch?v=a4NvKBiUc70

could be a bad ground, or a bad lead. It just seems to be a problem when you put the system under load. To me it would be an alternator, but you can tell that really quick with a voltmeter. Im still leaning towards alternator until it is ruled out

I think it's time to trade it in on a Mustang... But that's just me. ;)

2006GT wrote:I think it's time to trade it in on a Mustang... But that's just me. ;)

i agree...

No pressure... But Come on man everyone is doing it.

yea you wanna be cool dont you

Do it! I am guessing the alt as well.

Sounds like you need a mustang. I'll sell you mine for 17K. Lol

Thats a good deal for a 12.3 sec car.

MrClark wrote:2002 chevy trailblazer.... changed battery cause it died.... now car idles really rough (300 to 900 to 300 to 900 rpm's and eventually dies with AC/Heater on... turn AC/Heater off and runs smooth...

any thoughts as to what made it start doing this during a battery change........?

This right here is your problem!!

03.sonicblue wrote:Thats a good deal for a 12.3 sec car.

Thats two. Thats enough. The people have spoken.

MrClark wrote:2002 chevy trailblazer.... changed battery cause it died.... now car idles really rough (300 to 900 to 300 to 900 rpm's and eventually dies with AC/Heater on... turn AC/Heater off and runs smooth...

any thoughts as to what made it start doing this during a battery change........?

May just be a fluke that it happened after the battery but I just had an 2003 Trail Blazer 4.2 ltr. that would die with the ac on I fixed it

Oh yeah bet you thought I was going to leave you hanging haha it was the throttle body cleaned it up and presto worked great

I was thinking it could be your throttle body as well.

Washer fluid... ya that's it.

could be the muffler bearings

2006GT wrote:Washer fluid... ya that's it.

Tire Pressure?!

wow.. so i checked my tire pressure... added 3 lbs to my right rear.. and presto.. everything is fine....


ok for real though... the heater on without the AC on .. car idles fine.... turn on AC and it idles rough and dies.... Alternator checked out fine... going to clean the TB tomm and see what happens.. thanks greg

Hmm... Vaccum leak? Compressor locking up causing it to drag?

Sounds like it's dragging.

Hows your Air filter look?