Major power loss w/ AC on

[mentalattica]

Hey Guys,

I have a 2007 Yukon SLT 5.3 w/AFM
46,000mi - w/3.42 - All Stock - Original Stock Plugs n Wires

I've noticed in the summer months a HUGE power loss when my AC is on. Acceleration from a dead stop is pretty terrible, and passing on the highway is almost impossible.

Last night I accidentally almost caused an accident on the interstate trying to pass a slow driver. The car in front of me was going about 40mph in a 60mph (most people drive about 65-70ish). There was more than enough time for me to pass in my opinion, so the driver behind me and I switch lanes to pass and I floor it literally, with the pedal all the way to the floor I gained maybe 5mph in 3-5 seconds. This caused a few cars in that lane to slam on their brakes or switch lanes at the last second. The car that switched lanes with me was going the same speed as me and literally blew me out of the water when it passed me, it was a Kia Spectra. It's felt like my truck was never going to downshift! RPMs barely moved above 2000.

So I tried to repeat the scenario a few times on the way home, and I have zero acceleration when my AC is on. I turned the AC OFF and it's 200% more responsive, I can pass with ease, flooring it actually gives me the WOT feel, and there's a 1-2 mpg increase.

My question is why is my AC taxing over 50% of my engine's power? I don't think it's time for a tune-up. Is there anywhere else I should look? I dread towing anything and having to use my AC, it feels like a Ford ****** pulling a Yacht....

 

[GM Customer Service]

mentalattica,

Typically you should replace your plugs and wires at the 100,000 mile mark. However, depending on how you drive and the driving conditions you could possibly have to replace them sooner. Have you brought this issue to your dealerships attention?

Thank you,

Elizabeth, GM Customer Service

 

[DJPoertsch]

I have the same problem. I lose a lot of power when my compressor switches on. I have already changed new spark plugs, ignition cables and the ignition coils. As soon as the compressor is switched on it feels like it is running on 4 cylinders. But only when it turns on. Three days ago I carried out a professional air conditioning service with an extraction leak test and refilling. Could it be that the air conditioning compressor is defective?

 

[DJPoertsch]

Here I found some information about our Problem, but I can't figure out how this solution will fit together that this throttle Body cleaning would solve the Problem with the reduce of power at that much what I feel when my compressor is turning on.

Dramatic loss of Power with AC on

My 5.3 feels like a 4 cylinder when my a.c. is on, it's hot out, and the clutch fan is engaging. I've read that some notice a loss of about 10-20hp and then others notice no loss at all. Is there a common issue that can cause this and doesn't anyone know of any fix? Sent from my SM-G955U using...

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