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99 Silvy 4.8 question


red00lght
04-16-2005, 02:44 PM
My truck has a problem. If I turn my A/C on, as I accelerate down the road and it kicks on and off, it is causing the truck to hesitate a little as it cycles on. You can even hear the engine tone change slightly and it defintely feels like it is under a much greater load and having to work hard to accelerate. It is just bad enough to be really annoying. :disappoin

My question for the 4.8 owners is if they have felt the same thing as the A/C kicks on/off? If I leave the A/C off, the truck accelerates smoothly.

Thanks!

kenny-1907
04-16-2005, 06:05 PM
If i remember correctly my truck does the same thing. The AC really sucks the alot of power to turn, hell there was even a noticeable difference on my 96 sierra with the 5.7. I wonder if an underdrive pulley set would help with this ? ?

BlenderWizard
04-16-2005, 06:36 PM
I've got a 5.3 in mine, and it doesn't seem to make much difference with the a/c on

red00lght
04-17-2005, 01:33 PM
I knew I should've gotten the 5.3!! :banghead:

I'm still surprised at how much of a difference the A/C makes, but I need to tune up my truck a little anyways since it is stumbling a bit at idle.
Thanks for the reply!!

nineball481
04-18-2005, 04:27 PM
I have the 4.8, I haven't noticed that much of a bog when the ac kicks on. Then again the last time I used the AC was about 6months ago....

kenny-1907
04-18-2005, 06:01 PM
There will be a bit of a change when it kicks in , but if it is really noticeable you may have something going on there. There is a decrease in power when i have my A/C on but i don't notice it when it cycles on and off. Maybe your TB or the IAC needs cleaning........just a thought.

01Blackerado
04-19-2005, 08:30 AM
The AC should only cycle when you have the vent control turned to windshield de-fog, or basically anywhere to the right of the feet only selection!! When its on face or feet and face or anywhere to the left of feet only...then it should stay on constantly unless you turn it off using the AC button!!
As for the bogging...it sounds to me like you need a tune up! Try this and let us know how it goes:
*Sparkplug- NGK TR55's gaped .500-.600
*Clean out Intake tube and Throttle body blade(only use a towell or cloth)
*Use 93 octane and on the first fill-up throw in some injector cleaner!
*Change the fuel filter(do this AFTER you injector clean, because the old filter will pick up alot of crap and gunk after the cleaner runs through it)

If you want to improve the truck's performance drastically!!! Get some electric fans!!! They will free up alot of HP and TRQ by taking the stock fan, Weight and drag resistance, off the crank!!!

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