weird idle..plz help

[rustic]

ive got a 2003 tahoe with the 4.8.

Had to change alternator which led to changing the battery. its a duralast from autozone with 1000 cranking amps. not sure if it is the correct battery. the wife went get it.

anyway, the truck idles as low as 400 then jumps to about 800 every 15 seconds or so. if i have the AC on it has died out while im in park on the brake.

i took off the air intake to get to the belt to take the alternator off. could i have screwed the idle?

i notice my HID's have a subtle blink every now and then. should i be concerned with that?

any advice is appreciated.

 

[dye4metal]

sounds like the alternator is running to low. but you should check you put the airfilter and all make on correctly. pay attention that the MAF is on correctly too.

 

[shadow]

Check you battery cables for corrosion. Clean them good or replace is really bad. Mine got bad (positive cable connector) due to defect in the original AC Delco battery (the postive post became loose and leaked gas and acid out of it onto the connector) and caused problems for me until I replaced the battery and cleaned it real good.

Hope this helps.

 

[ZX1100F1]

Please tell us that you didn't get the new alternator from AutoZone?

 

[rustic]

yes i got the alternator from autozone. why shouldnt i have?

My problem was i didnt check my work and i forgot to plug in the connection by the air box.

my wife got the reconditioned alternator that they had in stock.

 

[Jhowe2k]

You need to clean your throttle body. I had the same probs. My volts were all over the place, stalls at idle, you name it. I replaced batt and alt to no benefit. Finally after I had installed my alt I noticed the Throttle body was gunked up ( I had to remove the intake tube to get to the alt bolts). I got a can of cleaner and it took about 15 minutes. My idle went from 400 to 550 after the cleaning. You see, with the gunked TB causing the low idle, my alt wasnt turning quick enough to provide 12V to the electrical system (which obviously means fuel injectors too). Clean that and you should be fine.

-Jared